OBJECTIVE: This in vitro study aimed to evaluate the influence of different surface treatments, 3 luting agents and thermocycling on microtensile bond strength (µTBS) to zirconia ceramic. Material and METHODS: A total of 18 blocks (5x5x4 mm) were fabricated from zirconia ceramic (ICE Zirkonia) and duplicated into composite blocks (Alphadent). Ceramic blocks were divided into 3 groups (n=6) according to the following surface treatments: airborne-particle abrasion (AA), silica-coating, (SC) (CoJet) and silica coating followed by silane application (SCSI) (ESPE Sil). Each group was divided into 3 subgroups (n=2) according to the 3 luting agents used. Resin-modified glass-ionomer cement (RMGIC, Ketac Cem Plus), self-adhesive resin cement (UN, RelyX Unicem) and adhesive resin cement (ML, MultiLink Automix) were used for bonding composite and zirconia blocks. Each bonding assembly was cut into microbars (10 mm long and 1±0.1 mm²). Seven specimens of each subgroup were stored in water bath at 37oC for 1 week. The other 7 specimens were stored in water bath at 37oC for 30 days then thermocycled (TC) for 7,500 cycles. µTBS values were recorded for each specimen using a universal testing machine. Statistical analyses were performed using a 3-way ANOVA model followed by serial 1-way ANOVAs. Comparison of means was performed with Tukey's HSD test at (α=0.05). RESULTS: µTBS ranged from 16.8 to 31.8 MPa after 1 week and from 7.3 to 16.4 MPa after 30 days of storage in water and thermocycling. Artificial aging significantly decreased µTBS (p<0.05). Considering surface treatment, SCSI significantly increased µTBS (p<0.05) compared to SC and AA. Resin cements (UN and ML) demonstrated significantly higher µTBS (p<0.05) compared to RMGIC cement. CONCLUSIONS: Silica coating followed by silane application together with adhesive resin cements significantly increased µTBS, while thermocycling significantly decreased µTBS.

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Bond strength of three luting agents to zirconia ceramic - influence of surface treatment and thermocycling

A combustion safety device for the counter-action against oxygen deficiency in a gas heater which is provided with a main burner of the surface combustion type and with an oxygen-deficiency detecting burner of a Bunsen type, in which a primary-air hole of the oxygen deficiency detecting burner is made to communicate with the primary-air supply chamber or distributing chamber of the main burner.

Combustion safety device for a gas heater

The present invention provides an oriented substrate for forming an epitaxial thin film thereon, which has a more excellent orientation than that of a conventional one and a high strength, and a method for manufacturing the same. The present invention provides a clad textured metal substrate for forming the epitaxial thin film thereon, which includes a metallic layer and a silver layer bonded to at least one face of the metallic layer, wherein the silver layer has a {100} cube texture in which a deviating angle Δφ of crystal axes satisfies Δφ≦9 degree. The textured metal substrate can be manufactured by subjecting the silver sheet containing 30 to 200 ppm oxygen by concentration to the orienting treatment of hot-working and heat-treating, and bonding the metal sheet with the oriented silver sheet by using a surface activated bonding process.

Clad textured metal substrate for forming epitaxial thin film thereon and method for manufacturing the same

The process produces a stabilized zirconia powder by first contacting zirconium basic carbonate particles with a stabilizer compound. This reacts the zirconium basic carbonate particles with the stabilizer compound through heterogeneous contact to form a stabilized zirconia precursor. The stabilizer compound is for stabilizing a phase structure selected from the group consisting of tetragonal phase, cubic phase and mixtures of tetragonal and cubic phases. And calcining the stabilized zirconia precursor removes gaseous by-­products and forms the stabilized zirconia powder. The stabilized zirconia powder has a phase structure selected from the group consisting of tetragonal, cubic and mixtures of tetragonal and cubic.

Method for manufacturing stabilized zirconia

The invention relates to a powdery zirconium oxide containing metal oxides from the group of scandium, yttrium, rare earths and/or the mixtures thereof. The invention also relates to a method for their production and to their use in fuel cells, in particular for producing electrolyte substrates for ceramic fuel cells.

Zirconium oxide and method for the production thereof

A zirconium oxide sintered body for an oxygen concentration sensor is produced by mixing 87.5 to 91.0% by weight of zirconium oxide powder, 8.5 to 12.3% by weight of yttrium oxide powder, 0.5% by weight or less of silicon oxide and 0.2 to 1.0% by weight of aluminium oxide, drying the resulting mixture, followed by sintering so as to make the cubic phase content in crystal phase of the resulting sintered body at ordinary temperatures 95% by weight or more. Such zirconium oxide sintered bodies have excellent mechanical strength, ionic conductivity and thermal shock properties and can be used stably for a long period of time.

Process for producing zirconium oxide sintered body

PURPOSE:To provide a combustion safety device which operates a safety device through detection of incomplete combustion when it occurs, by a method wherein an outer peripheral electrode of a tubular sintering material of oxygen ion conductive solid electrolyte is disposed so that it is forced into contact with an oxidating flame during oridinary combustion and it is forced into contact with a reduction flame during incomplete combustion. CONSTITUTION:A sensor 1, which is formed by a ziliconia stabilized by means of yttria and has an inner peripheral and an outer peripheral electrode formed by baking platinum paste on its inner and outer peripheral surface. With a main burner 5 ignited, the sensor 1 is heated, a high electromotive force of about 800mV is generated, and an electromagnetic valve 6 is held in an opening state by dint of such electromotive force. When incomplete combustion occurs due to some cause, a combustion flame is stretched, a reduction flame A is forced into contact with the outer peripheral electrode and the sensor 1 is reduced in temperature. Besides, an oxygen partial pressure ratio at the inside and outside is decreased, the electromotive force is reduced, and the electromagnetic valve 6 is forced into a closed state to stop the supply of gas.

Combustion safety device

PURPOSE:To enhance oxygen ion conductivity, heat shock resistance and high temp. stability, by baking an electrode simultaneously with the sintering of zirconium oxide ceramics containing a specific component. CONSTITUTION:A particulate material containing 87.5-91.0wt% of ZrO2, 8.5- 12.3wt% of Y, 0.5wt% or less of SiO2 and 0.2-1.0wt% Al2O3 and having a crystal phase containing 95wt% or more of a cubic crystal at a room temp. is molded under pressure and the molded one is heat treated at a temp. of a sintering temp. or less to form a temporarily sintered molded body. An electrode material is applied to the molded body and heated to a high temp. to be baked simultaneously with sintering to form an electrode. When Y2O3 exceeds 12.3 wt%, mechanical strength is lowered and, when it is below 8.5wt%, a monoclinic zirconium oxide crystal is too much formed and a strength lowering amount in a heat cycle test becomes large. When Al2O3 exceeds 1.0wt% and SiO2 exceed 0.5wt%, ion conductivity is lowered.

Oxygen sensor and manufacture thereof

PURPOSE: To integrally form a large or complicated-shape material by obtaining excellent superconducting junction without deteriorating characteristics of high temperature superconductors to be junctioned together CONSTITUTION: In a method to junction mutual high superconductors 2 and 2' formed on a base material (a silver plate) 1, a high temperature superconductor precursor 3 mainly composed of an amorphous body is interposed between the high temperature superconductors 2 and 2' to be junctioned together Next, the high temperature superconductors 2 and 2' are junctioned to each other by heating them at a temperature where a high temperature superconductor crystal formed on the base material 1 does not decompose and/or melt and the interposed high temperature superconductor precursor 3 crystallizes

Manufacture of high temperature superconducting junction body

PURPOSE:To obtain the title part having a few broken pieces and cracks caused by thermal shock and mechanical strength, slightly wearing itself, having a little wear of papermaking net sliding on the part, comprising alumina ceramics containing a specific amount of zirconia component mostly made of tetragonal system phase CONSTITUTION:The objective part comprising alumina ceramics containing 20-40wt% zirconia component (preferably zirconium oxide, hafnium oxide and cerium oxide are contained and the amount of cerium oxide is 3-15mol% based on zirconium oxide and hafnium oxide) mostly made of >=80% tetragonal system phase Alumina has preferably =500MPa flexural strength

Nakada Takao

Papers

Process for producing zirconium oxide sintered body

Combustion safety device

Oxygen sensor and manufacture thereof

Manufacture of high temperature superconducting junction body

Part of supporting papermaking net for paper machine