Showing papers on "Surface finishing published in 1987"

Optical glass fabrication technology. 2: Relationship between surface roughness and subsurface damage.

Abstract: For glass grinding conditions where fracture is the principal mechanism, a constancy is found between the depths of surface roughness and subsurface damage. For a range of experimental conditions we find the ratio of subsurface damage to surface roughness to be 6.2-6.4 for bound diamond abrasive grinding. This is larger than the value reported for loose abrasive grinding (3.7-4.0). The constancy of this value has great practical importance. From a measurement of the surface roughness one can obtain an accurate estimate of the damage layer thickness that must be eliminated by polishing or subsequent grinding operations.

Surface characterization of InP using photoluminescence

Abstract: Photoluminescence (PL) measurements have been performed on InP samples in situ during various surface treatments including chemical etching, wet anodization, and low-pressure chemical vapor deposition. It was found, in agreement with previously published results, that the magnitude of the PL signal varies markedly with surface treatment due presumably to changes in either surface-state density, and/or surface potential. In an attempt to assess the effectiveness of this noninvasive method as a tool for characterizing and monitoring the progressive development of a semiconductor surface during processing, a number of experiments on InP have been performed. The results indicate that although some uncertainty may exist in assigning a mechanism for the PL change in any given experiment, the general trend appears to be that surface degradation results in a reduced signal. As a result, process steps which enhance the PL intensity are likely to be beneficial in the preparation of a high-quality interface.

Degradation Mechanisms in Tin- and Gold-Plated Connector Contacts

Abstract: Degradation mechanisms in tin-plated contacts (Sn contacts) and gold-plated contacts (Au contacts) are clarified. Contact resistance and corrosion characteristics for both types of contacts are investigated and compared. Contact resistance is more stable for Sn contacts than for Au contacts in a SO 2 + NO 2 + C1 2 atmosphere. This is because relatively few corrosion products are formed on Sn contacts. Also, the surface films formed on Sn contacts shatters more easily upon plastic deformation. Corrosion experiments in atmospheres containing different combinations of SO 2 , NO 2 , and Cl 2 demonstrate that two types of corrosion processes take place in plated contacts. One is surface corrosion which occurs when the surface finish is severely attacked by a corrosive atmosphere. The other is pore corrosion which occurs when the underplating materials are attacked to a greater extent than surface corrosion. Both processes occur in Sn contacts and the former is dominant in atmospheres containing Ci 2 . On the other hand, only pore corrosion occurs in Au contacts. Furthermore, galvanic corrosion either enhances or inhibits the formation of outcroppings in the pore corrosion process, depending on the electrode potential of the surface finish and underplating materials.

Materials and surface finish effects in the breaking-in process of engines

Abstract: In this investigation, three materials and several surface finishes on cylinder walls were compared in laboratory tests that simulate the running-in behavior or fired engines. The three materials were the conventional cast gray iron, a sintered graphite-iron powder, and a cast aluminum-silicon alloy. The surface finishes were formed by various types of polishing and honing, including ''plateau honing.'' The run-in behavior of these materials was indicated by a laboratory simulator that is known to correlate with the early wear seen in fired engines. Two test sequences were used. One is a scuff test, in which a quick succession of increasing contact pressure is applied between a piston ring and a cylinder wall until surface failure occurs. The other is a ''normal'' wear test in which a lower contact pressure is applied, for a longer term study of surface change and coefficient of friction. Scuff load and midstroke friction were found to be dependent on roughness but independent of the amount of plateauing, as measured by skewness of the height distribution in the surface roughness trace. Plateau-honed cylinders were found to run in no more quickly than uniform-honed cylinders. Graphite-iron powder and aluminum-silicon cylinder walls had lower scuff resistance than didmore » gray iron, but their ''normal'' wear behavior and midstroke friction performance were about the same as gray iron.« less

The emissivity of etched Cu‐Nb in situ alloys

Abstract: Cu‐Nb in‐situ alloys possess high strenght plus thermal conductivity properties and are therefore of interest in heat transfer applications. Etching the surfaces of these alloys to preferentially remove Cu places the Nb filaments in relief. Experiments demonstrate that the emissivity of such etched surfaces can be increased from around 0.08 to values greater thana 0.9.

Multistage finishing device and method

Abstract: A vibratory finishing machine (10) for the surface finishing of workpieces comprising an essentially spiral trough (32), having a plurality of channels in side-by-side relationship, resiliently mounted for vibration and tilted with respect to the horizontal; such a spiral trough which is employed as a finishing chamber by attachment to a resiliently-mounted vibratory structure of a vibratory finishing machine; and a method and apparatus for vibratorily finishing a workpiece by subjecting it to a surface finishing medium in such a trough, having liquid finishing medium in only lower sections thereof and having solid finishing medium in an outer channel of said trough.

Concrete slab surface finishing tool

Abstract: A concrete slab hand finishing tool is provided with, in combination, a flat floor surface working area, a lip offset surface working area joined to the flat floor surface working area, a flat lip surface working area joined to lip offset working area, and an edge surface working area joined to the flat lip surface working area.

Precision Finishing Of Ceramics

Abstract: The manufacture of advanced ceramic components requires high accuracy and repeatibility in the control of the fabrication process. Surface finish in the nanometer range and excellent figure accuracy can be achieved if material can be removed from the surface without causing brittle fracture. To define the mechanism of "ductile" material removal, a series of experiments were initiated involving two processes: single-point diamond turning and diamond-wheel grinding. The results indicate that at small depths of cut, using stiff, well controlled machine tools, ceramic materials like silicon, silicon carbide, and germanium can be machined in a ductile regime.

Corrosion Properties of Surface-Modified Materials

Abstract: Surface modification processes provide unique ways to change the surface and near-surface regions of materials, resulting in significantly improved surface-sensitive properties (i.e., corrosion, oxidation, wear and fatigue crack initiation). In the area of corrosion behavior, three new widely divergent, but largely complimentary surface modification techniques are yielding impressive results—laser surface alloying (LSA), ion implantation and ion plating.

Manufacture of super abrasive grain grindstone for mirror-like surface finishing

Abstract: PURPOSE:To obtain a grindstone which can do finishing with flatness of high degree and without producing flaws on the surface of a work piece by using the manufacturing method of mixing abrasive grains of diamond or the like with an abrasive support such as iron powder, copper powder or the like and a bonding material such as phenol resin or the like and forming under pressure and caking. CONSTITUTION:First, copper powder is added and mixed with liquid phenol resin and then diamond grains are annexed and further is added powder phenol resin, and after mixing them well, the mixture is formed under pressure by means of dies and then is hot-baked. The grindstone produced under this manufacture has the structure wherein diamond grains 1 are scattered around copper powders 2 and in contact with them and blow holes 3 are mingled at an appropriate proportion, the state of which is bonded by means of phenol resin 4. When the grindstone is used to finish a specular face, jutting diamond grains are embedded with plasticity into metal powders which are abrasive grain support, and diamond grain cutting blades are almost evenly arranged, so that deep cutting flaws can not be produced.

Coating formulation and method for refinishing the surface of surface-damaged graphite articles

Abstract: The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

Computer Controlled Ion Beam Machining For Precision Surface Finishing And Figuring

Abstract: Micromachining of mechanical structures by ion bombardment is reported. A 1.5 kV argon ion beam is used under computer control for workpiece stock removal. Generation of profiles with submicron precision is demonstrated and computer algorithms are used to predict machining conditions for producing specific surface characteristics and evaluating them geometrically.

Surface treatment of material

Abstract: PURPOSE:To enable a surface treatment with high plating adhesiveness and less surface ruggedness by forming a conductive layer consisting of conductive reinforcing materials, conductive fillers and synthetic resin on the surface of a base material and curing said layer, then subjecting the layer to surface finishing and electroplating. CONSTITUTION:The conductive layer A formed by homogeneously and integrally including the conductive reinforcing materials or the reinforcing materials 1 imparted with electrical conductivity and the granular and flaky conductive fillers 2, 3 into the epoxy resin 4 is formed on the surface of a composite material layer B and is cured. The surface of the curd layer A is then finished by machining to a smooth surface at a prescribed finishing allowance while the conductive reinforcing materials 1 and conductive fillers 2, 3 embedded in the epoxy resin 4 are exposed on the surface. The machined surface is further subjected to the electroplating or electroless plating to form the plating film integrated with the conductive reinforcing materials 1 and the conductive fillers 2, 3. The plating film which is smooth and has high exfoliation strength is thereby formed on the composite material layer B.

Remote gate capacitance‐voltage studies for noninvasive surface characterization

Abstract: A measurement technique has been developed which allows noncontact capacitance-voltage measurements to be made using a gate electrode located remote from the semiconductor surface under study. With gate electrodes about 0.5 mm in diameter and gate to semiconductor separations of about 1500 A, it was possible to generate data entirely comparable to that obtained with integrated MIS structures but with the advantage that there was access directly to the free-semiconductor surface. This technique was applied to bulk single-crystal Si and InP samples.

Visible‐laser etching of refractory metals by surface modification

Abstract: A two‐step laser etching technique for Mo and W films is described. In the first step, the laser modifies the chemical composition of the metal surface; in the second, deep etching of the pre‐exposed areas is by broad‐area heating in a reactive ambient. The surface modification takes place in the presence of Cl2, which etches the native‐metal oxide and replaces it with a more volatile metal halide. Deep etching is performed with NF3. Since the native oxide is resistant toward etching with NF3, the second step is selective with respect to the laser‐halogenated area and is, in effect, a chemical amplification of the surface modification. Well‐delineated, high‐contrast patterns are obtained with this method.

Polishing of semiconductor crystal material

Abstract: PURPOSE:To prevent generation of noxious gas, impart corrosion resistance and permit maintenance of good machining efficiency and accuracy in mirror surface finishing of semiconductor crystal material by using aqueous abrasive liquid containing more than 0.5% by weight of an oxidizing agent and 0.5-20% by weight of suspended colloidal silica. CONSTITUTION:Abrasive liquid prepared by suspending or solving in pure water about 5% by weight of colloidal silica in which SiO2 has an average particle diameter of about 800Angstrom with the concentration about 40% by weight and the pH is in the order of 9-10.5 and about 10% by weight of sodium percarbonate and an abrasive cloth prepared by coating artificial leather with a polyurethane resin can be used to polish a work of CeTe or other semiconductor crystal material with no generation of noxious gas in a corrosion resistance manner, causing easy handling and long life of the machine, so that high precision mirror surface finishing can be carried out at a proper machining efficiency. Excessive concentration of the oxidizing agent and colloidal silica results in poor effect.

The influence of construction procedures on abrasion resistance. concrete durability. katherine and bryant mather international conference, held at atlanta, georgia, usa, 27 april-may 1987

Abstract: A test method, based on rotating steel wheels running in a circular path, has been adopted to assess the abrasion resistance of concrete. The reported data are from a series of tests performed on relatively large slabs. It was, therefore, possible to employ normal construction procedures and plant, including power finishing and vacuum dewatering with hand finishing merely being employed for comparison. Additional tests were undertaken to assess the influence of curing methods. Power finishing significantly increased abrasion resistance, with the benefits being directly related to a number of applications of power trowelling. This is attributed to surface compaction and to reduction of the water-cement ratio of the surface matrix. Indeed, repeated power trowelling reduced the influence of mix design on the abrasion resistance, with all specimens achieving a similar surface matrix. Vacuum dewatering also increased the abrasion resistance with the applied suction leading to a reduction in the water-cement ratio and an increase in the cement content of the surface layer. This process was most effective on concrete with a high, initial water-cement ratio. Efficient curing significantly increased the abrasion resistance. While no significant differences were detected between the abrasion resistance of slabs cured by wet burlap or plastic sheeting, the plastic sheeting method was less susceptible to error. Curing compounds were very beneficial, with their efficiency being very dependent on the texture of the applied surface. In summary, while mix design clearly influenced the abrasion resistance, attention to both construction procedures and curing could achieve similar changes in abrasion resistance. (Author/TRRL)

Diamond turning of silicon for optics applications

Abstract: The goal of this study is to examine the feasibility of fabricating silicon optical surfaces by diamond turning. Our approach has been to machine small slices of single crystal silicon using a range of process parameters similar to what has typically been employed with ductile materials. In this manner, a set of conditions has been bracketed which has yielded good values of surface finish as measured by stylus profilometry, and low levels of surface damage as indicated by scanning electron microscopy. The surfaces generated thus far have also yielded information of a fundamental nature which relates to the turning of brittle materials in general. Recommendations for further work are suggested to maximize the material removal rate without compromising surface quality, to quantify any tendency to generate figure errors, and determine what problems are involved in scaling the process to larger surfaces.

Evaluation And Specification Of Micro-Machined Optics For Laser Printing

Abstract: The quality of optical surfaces generated by single-point diamond machining has been evaluated for laser printing applications. Microfinish topography of the surfaces has been analyzed by differential bidirectional laser scattering. Random and periodic surface structure, derived from the Fourier transform of the scattered-light power spectrum, are compared with interferometric surface roughness measurement. Surface tolerance may be specified for a class of laser printers by comparing the scattered intensity distribution with the analytical model of image degradation due to optical scattering. Roughness parameters have also been characterized as a function of tool radius and feed rate. Surface flatness and relative surface parameters are measured for a polygonal laser deflector. Measurement techniques are described. The characteristics of some commercially supplied micro-machined optics are discussed.

Effects of Surface Finishing Conditions and Alloying Elements on the Structure of an Iron Molybdenum Boride Base Hard Alloy

Abstract: Synopsis : A recently developed iron molybdenum boride base hard alloy has good mechanical properties, excellent wear and corrosion resistance. This hard alloy produced by liquid phase sintering consists of a hard phase composed mainly of a Mo2FeB2 type complex boride and an iron base, stainless steel-like binder phase. In the present investigation, both the effects of surface finishing condition on the binder phase and the effects of alloying elements on the structure and alloy partitioning were studied by X-ray diffractometry, Auger analysis, transmission electron microscopy, etc. Results indicate that the binder phase of the alloy becomes martensitic or austenitic depending on the alloy composition and sintering conditions, and that sometimes the martensitic transformation of the austenite in the binder phase is induced by surface grinding. This hard alloy contains the Fe2B or M6C (M : metal) phases depending on the composition in addition to the Mo2FeB2 type complex boride and an iron base binder phase. A martensitic binder of the alloy seems to give higher transverse rupture strength and hardness than an austenitic binder.

Production of surface hardened body of screw or the like for injection molding machine

Abstract: PURPOSE:To easily produce a surface hardened body having high accuracy at a low cost by working a tempered base material, coating the surface thereof with ceramics, temporarily calcining the coating and subjecting the material to finished working to the final size then to normal calcining and surface finishing. CONSTITUTION:The tempered base material is worked to the size slightly smaller than the final finish size and thereafter the surface of the base material is coated with the ceramics to the size slightly larger than, the final finish size. The coated base material is temporarily calcined to the extent that the above-mentioned ceramic particles have suitable binding strength and thereafter the base material surface is worked to the final finish size. The base material is then immersed into a soln. of a chromic compd., etc., as necessary, to impregnate said compd. into the ceramic pores. The base material is subjected to the normal calcining to form the thoroughly calcined body securely bound with the ceramic particles; further the base material is subjected to surface finishing such as finishing by polishing. The surface hardened body of a screw for an injection molding machine, etc., is thus obtd.

Stretching device of thermo-plastic resin sheet

Abstract: PURPOSE:To provide a bi-oriented film without gauge mottles, unevenness of scuff marks caused by adhesion by utilizing a roll of roughened surface finishing specifying roll Rmax value, the number of concave and the height of convex. CONSTITUTION:The process of precision finishing such as ultra finishing with small margin for finishing after abrading the roll surface with a comparatively rough whetstone, the process of precision finishing after blasting, or the combination of both of the said processes are carried out by utilizing a roll having more than 10 pcs./mm of convex, Rmax more than 1.0mum and less than 6.0mum and the height of convex not higher than 1.5mum than the centerline of section area. By utilizing the said roll, neither adhesion phenomenon of the roll and sheet or the roll and film, nor scuff marks are created, when the roll is heated up more than glass transition temperature.

Manufacture of synthetic resin foamed sheet for floor covering with rugged pattern

Abstract: PURPOSE:To contrive to improve the decorativeness of a sheet by a method wherein, first, pattern is printed on a base fabric with printing ink containing foam-inhibitor and then dried; secondly, expandable synthetic resin paste sol is applied over the whole surface of the base fabric and dried; thirdly, coloring synthetic resin paste sol is applied uniformly onto said expandable synthetic resin paste sol and finally the sols are expanded so as to form convexities due to the expansion of the sols excluding the sols at the portion corresponding to the printed pattern. CONSTITUTION:First, pattern is printed onto the top surface of a base fabric 2 and dried. Secondly, in addition, expandable synthetic resin paste sol C is applied onto said top surface and dried. Thirdly, coloring synthetic resin paste sol A for surface finishing is applied onto said sol C and then heated. Accordingly, said heating causes the expandable synthetic resin paste sol C to expand itself. However, the expansion of the printed pattern portion, which is printed with ink containing foam-inhibitor, is suppressed. Consequently, as a whole, rugged pattern is formed. In this case, because the color tone at concavities 12 is different from that at convexities 13, the finish of a product has the texture and design like that of multi-color printing and consequently large decorative effect can be obtained.

Method of mirror surface finishing for stainless steel

Abstract: PURPOSE:To reduce the surface roughness of stainless steel with a uniform surface structure, by carrying out mirror surface finishing of stainless steel with the use of a process consisting of first successive polishing steps with the use of grind stones, a second polishing step with the use of a solution of nitric acid containing chromium oxide and a third lapping step with the use of a nitric acid solution. CONSTITUTION:The surface of stainless steel W is subjected to mirrored-surface-finishing with the use of a process consisting of first successive polishing steps with the use of grindstones 20' having grain sizes of 600-1,200, a second polishing step with the use of a first solution containing 2.5-3.5% nitric acid and 4.5-5.5% of chromium oxide powder at a temperature of 28-32 deg.C and also with the use of a felt or unwoven lapping material 20'' and a third lapping step with the use of a second solution containing 4.5-5.5% of nitric acid together with a lapping material similar to the lapping material 20'' used in the second step. Then, the structure of the finished surface may be made to be uniform having an extreme small surface roughness. Accordingly, it is possible to fabricate the outer surface of stainless steel with a high degree of accuracy, having a uniform mirror surface. Further, if the outer surface of stainless steel is colored with a coloring process, such as, for example, INCO process, an excellent colored mirror surface having an extremely small difference in color may be obtained.