Showing papers on "Titanium powder published in 1986"

Combustion synthesis of titanium carbide: Theory and experiment

Abstract: The combustion synthesis of titanium carbide from elemental powders has been theoretically and experimentally studied as a model system for self -propagating high temperature synthesis (SHS) of refractory compounds. Calculations of the adiabatic temperature of combustion of graphite and titanium powders to form TiC x have been made to show the effects of stoichiometry, dilution and the initial temperature of the reactants. Experimental observations on the stability of the combustion front, combined with theoretical predictions, lead to an estimated activation energy of ≤ 117 kJ mol−1 for the process. This value is at least a factor of about four too low to correspond to a diffusion-controlled process. The combustion of graphite and titanium powders was accompanied by the evolution of gases whose primary constituent was found to be hydrogen. This observation was attributed to the reaction of adsorbed moisture with titanium powder. The titanium carbide phase resulting from the combustion of compacted mixed powders of the elements was highly porous (∼ 50% porosity). It can be obtained in high density (∼5% porosity) when pressure is applied during the combustion process.

Processing of iron-titanium powder mixtures by transient liquid phase sintering

Abstract: Transient liquid phase sintering was examined for Fe-Ti powder mixtures. The experimental plan included the effects of several processing variables, such as green density, particle size, composition, heating rate, sintering temperature, and sintering time. During heating, pores form at the Ti particle sites. At the first eutectic temperature (1085 °C), liquid spreading is inhibited by a surrounding intermetallic envelope, leading to swelling. At the second eutectic temperature (1289 °C), the liquid penetrates along the iron grain boundaries and provides densification. The amount of densification depends on the amount of liquid formed at the second eutectic temperature and its duration as determined by the titanium content and heating rate.

Method of bonding ceramics and metal, or bonding similar ceramics among themselves; or bonding dissimilar ceramics

Abstract: A bonding method using, as bonding agent, brazing filler metal, or composite plating, or a combination of composite plating and ceramic spraying. In the first case, there are provided on the bonding region titanium powder and brazing filler metal alloyable with the titanium and having a lower melting point than titanium. The heating temperature is set higher than the melting point of the brazing filler metal but not so high to melt titanium. In the second case, the bonding region is coated with composite plating. Plating base material is made of metal alloyable with titanium and having a lower melting point than titanium. Titanium powder is diffused into the plating base material. The heating temperature is set higher than the melting point of the plating base material but not so high to melt titanium. In the last case, the bonding region is coated with the above composite plating, and further covered with ceramic spraying. The heating temperature is set in the same manner as the second case.

Heat treatment of ti-fe sintered alloy

Abstract: PURPOSE: To provide excellent tensile strength and elongation percentage,by subjecting a Ti-Fe alloy to heat treatment under specific conditions and by forming a metallic structure in which a new-precipitated phase separates out from a solid solution and forms into laminar state along the cleavage planes of solid solution grains. CONSTITUTION: A high-purity iron powder is added to a high-purity titanium powder by a specific weight percentage up to the eutectoid composition, and they are sufficiently blended. The resulting powder mixture is compacted and then sintered in a high-temp. vacuum furnace for a prescribed period. The resulting sintered compact is held at a temp. in a β single phase temp. region for a prescribed period and then hardened. The above compact is further held at a temp. within an (α+β) two phases temp. region for a prescribed period, which is hardened or is allowed to stand to be cooled. COPYRIGHT: (C)1987,JPO&Japio

Production of titanium-containing alloy powder

Abstract: PURPOSE: To economically produce titanium-contg. alloy powder having good quality with a simple production process by heating a mixture composed of titanium oxide powder and other metallic powder in a vacuum and subjecting the mixture to a wet treatment. CONSTITUTION: The mixture composed of the titanium oxide powder, the other metallic powder (Ni, Fe, Mn, Co, Cu, etc.), at least one kind selected from the oxide powder and chloride powder thereof and at least one kind selected from alkali metals (Li, Na, K, etc.), alkaline earth metals (Mg, Ca, etc.) and the hydride thereof is heated for about 1W5hr at about 900W1,300°C in an inert gaseous atmosphere or vacuum. The resultant reaction product is then subjected to the wet treatment to throw the same into water and to stir the water, by which the titanium-contg. alloy powder is obtd. The grain size of the titanium powder, the other metallic powder, etc. is preferably about ≤100 mesh and the grain size of the alkali metals, etc. is about ≤4 mesh. COPYRIGHT: (C)1987,JPO&Japio

Effect of mixing on the laws of combustion of charge mixtures

Abstract: The authors study the effect of homogenization conditions for multicomponent charges on the laws, conditions, and maximum temperature of combustion. Charges with the following components were studied: I) Ti, C, B, Me-bonding agent; II) Ti, Cr, C, Me - bonding agent. The charges were prepared from PTM titanium powder, PKh-1S chromium powder, PNE-1 nickel powder, PM-15TS soot, and amorphous brown boron powder. It is shown that the liberation of gas in the high-temperature reaction occurs mainly in the combustion wave, while the film of melted titanium prevents gases from escaping through the starting part of the sample. At combustion temperatures close to the melting temperature of the final product, the lamella formed can be scorched and surface defects can be healed.

Production of aluminum-titanium alloy powder

Abstract: PURPOSE:To obtain Al-Ti alloy powder suitable for production of a product having an improved electrical characteristic in the stage of converting a powder mixture composed of Al powder and Ti powder by a heating treatment to an Al-Ti alloy and crushing said alloy by controlling the density of the powder mixture and subjecting the powder mixture to the heating treatment. CONSTITUTION:The alloy powder is produced by subjecting the powder mixture composed of the aluminum powder and titanium hydride powder or the aluminum powder and titanium powder to the heating treatment to form the aluminum-titanium alloy and crushing the alloy. The heating treat is executed in this stage by controlling the density of the powder mixture to a 1/15d+0.35-1/15d+1.6 range (d is the average grain size of the titanium hydride powder or titanium powder in micron). The aluminum-titanium alloy powder suitable for the anode electrode of an electrolytic capacitor in thus obtd.

Production of alexandrite cat's eye

Abstract: PURPOSE:To obtain the title alexandrite cat's eye crystal exhibiting a clear cat's eye effect by heat-treating an alexandrite single crystal in titanium powder. CONSTITUTION:An alexandrite single crystal is firstly embedded in the powder of titanium dioxide or titanium trioxide contained in an alumina crucible. The crucible is then placed in an electric furnace and heat treatment is carried out, for example, at about 1,200 deg.C for about 100hr. Subsequently, the crystal is slowly cooled, for example, at 10 deg.C/hr cooling rate. Consequently, the titanium oxide is dissolved in the solid alexandrite crystal and a high-quality alexandrite cat's eye crystal exhibiting a clear cat's eye effect is obtained.