Ceramic Engine Components Research Articles

Effect of nano-crystalline TiO2 addition on reciprocating frictional behaviour of alumina ceramics

We report the effect of normal load and sliding frequency on the tribological performance of alumina ceramics in relation with nano-crystalline T iO2 addition. Tribological studies are conducted by reciprocating a silicon nitride ball on the prepared samples in dry condition in a linear reciprocating tribotester. Reciprocating friction tests are performed with sliding frequency of 15, 30, 45 and 60 Hz and at normal loads of 0.3, 0.5, 0.7 and 1.0 kg. The friction coefficient increases with increasing sliding frequency, normal load but decreases with nano titania addition. The coefficient of friction sharply increases at the level of sliding frequency from 30 Hz to 45 Hz. As the coefficient of friction gradually decreases with increase in T iO2 addition, it can be inferred that alumina ceramics with T iO2 addition upto 4 weight percent can be used as ceramic engine components, cutting tool inserts.

Microstructural effects on the sliding-wear resistance of pressureless liquid-phase-sintered SiC under diesel fuel

Abstract The sliding wear of pressureless liquid-phase-sintered (PLPS) SiC ceramics under diesel fuel lubrication was investigated. It was found that the sliding-wear behaviour under diesel fuel is similar to what is observed under lubrication with the chemically similar paraffin oil: initial mild, plasticity-controlled wear followed by severe, fracture-controlled wear, with a well-defined wear transition. Compared to paraffin oil, however, diesel fuel lubrication decreases the extent of the mild-wear regime and results in damage that is more severe due to its lower viscosity. Also, it was found that the wear resistance under diesel fuel decreases with increasing contact load and sliding speed. Subsequent investigation of the effects of the intergranular phase content, grain size, and grain shape demonstrates nevertheless that the wear performance of PLPS SiC under diesel lubrication can be improved via microstructural control by (i) decreasing the intergranular phase content, and (ii) decreasing the SiC grain size or increasing its aspect ratio. The results of this work are likely to have relevant implications for the design of wear resistant PLPS SiC ceramic components for diesel engines.

Powder Injection Molding of Ceramic Engine Components for Transportation

Silicon nitride has been the favored material for manufacturing high-efficiency engine components for transportation due to its high temperature stability, good wear resistance, excellent corrosion resistance, thermal shock resistance, and low density. The use of silicon nitride in engine components greatly depends on the ability to fabricate near net-shape components economically. The absence of a material database for design and simulation has further restricted the engineering community in developing parts from silicon nitride. In this paper, the design and manufacturability of silicon nitride engine rotors for unmanned aerial vehicles by the injection molding process are discussed. The feedstock material property data obtained from experiments were used to simulate the flow of the material during injection molding. The areas susceptible to the formation of defects during the injection molding process of the engine component were identified from the simulations. A test sample was successfully injection molded using the feedstock and sintered to 99% density without formation of significant observable defects.

Design and Fabrication of a Micro Reciprocating Engine

This paper presents an ongoing project of developing a micro reciprocating internal combustion engine. The engine is designed on the basis of a two stroke piston engine, but heavy modifications have been made to suit the 2D MEMS fabrication. All the engine parts are located in two layers. Piston seals are not used and leakage is prevented by the introduction of microgrooves on the piston, tight tolerance control and an extended contact area between the piston and the cylinder. With the assistance of a film of lubrication oil, these measures prove effective in preventing leakage. A new approach has been developed to fabricate high temperature resistant engine components at low cost. The approach relies on the UltraThick SU-8 Process (UTSP) to make micromoulds; then ceramic and metallic engine components can be produced based on the moulds. The UTSP is a UV lithography process for producing up to 1000 ?m thick SU-8 layers and the quality of the fabrication results can be compared with those made by using X ray exposure process in the same thickness. A complete microengine has been fabricated in SU-8 using the UTSP for test drive. High quality ceramic and metallic components have been produced based on the SU-8 moulds, proving the new approach is feasible for building

An experimental investigation of rotary diamond truing and dressing of vitreous bond wheels for ceramic grinding

Experiments of rotary diamond truing and dressing of vitreous bond grinding wheels were conducted to investigate the effects of feed, speed ratio, and overlap ratio on cylindrical grinding of zirconia. The applications of ceramic engine components with complex and precise form and the lack of technology for precision truing of diamond grinding wheels have driven the need to study the use of vitreous bond CBN and SiC wheels for form grinding of ceramics. Truing and grinding forces and the roundness and surface finish of ground zirconia parts were measured. By varying truing process parameters, a wide range of surface finish and roundness could be achieved. Experimental results showed that wheels trued at speed ratio below −1.0 could grind parts with fine surface finish and good roundness. The analysis of truing and grinding results showed the trend of increasing grinding force at higher specific truing energy and better surface finish at higher grinding force. The lack of speed control of the direct–drive, variable–speed truing spindle was observed and its effect on the reverse of direction of truing force at positive speed ratios was studied.

Mapping the surface temperature of ceramic and superalloy turbine engine components using laser-induced fluorescence of thermographic phosphor

An excimer laser-based system for mapping the surface temperature of turbine engine parts coated with thermographic phosphors has been developed. The intensities measured for Y 2O 3:Eu over the temperature range ∼500–750°C are presented. In addition, the data correction and error analysis algorithm is discussed. The overall accuracy of this intensity-based surface temperature measurement technique was estimated to be ±5%. Furthermore, surface temperature measurements obtained from a ceramic matrix composite and superalloy components are presented.

The relation between acoustic emission and damage caused by thermal fatigue and thermal shocks in structural ceramics: Ceramic Materials and Components for Engines, Proceedings of the 2nd International Symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 799–806. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesellschaft (FRG), 1205 pp. (1986)

The relation between acoustic emission and damage caused by thermal fatigue and thermal shocks in structural ceramics: Ceramic Materials and Components for Engines, Proceedings of the 2nd International Symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 799–806. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesellschaft (FRG), 1205 pp. (1986)

Fourth international symposium on ceramic materials and components for engines

The symposium might very well be summarized as a Swedish friend did, ‘In 1986 I visited the symposium and i had never seen so many cracked ceramic pieces in my life, but today most components seem to be running and running in engine tests without failure’. So we seem to have increased our knowledge over the last five years.

Non-Destructive evaluation of ceramic components for engines : Goebbels, K. Ceramic Materials and Components for Engines, Proceedings of the 2nd International Symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 779–787. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesselschaft (FRG), 1205 pp. (1986)

Non-Destructive evaluation of ceramic components for engines : Goebbels, K. Ceramic Materials and Components for Engines, Proceedings of the 2nd International Symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 779–787. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesselschaft (FRG), 1205 pp. (1986)

Non-destructive evaluation of ceramic components for engines : Goebbels, K. Ceramic Materials and Components for Engines, Proceedings of the 2nd International Symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 779–787. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesellschaft (FRG), 1205 pp. (1986)

Non-destructive evaluation of ceramic components for engines : Goebbels, K. Ceramic Materials and Components for Engines, Proceedings of the 2nd International Symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 779–787. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesellschaft (FRG), 1205 pp. (1986)

Non-destructive evaluation of ceramic components for engines : Goebbels, K. Ceramic materials and components for engines, Proceedings of the 2nd international symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 779–787. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesellschaft (FRG), 1205 pp. (1986)

Non-destructive evaluation of ceramic components for engines : Goebbels, K. Ceramic materials and components for engines, Proceedings of the 2nd international symposium, Lubeck-Travemunde (FRG) 14–17 Apr. 1986. pp. 779–787. Edited by W. Bunk and H. Hausner, Verlag Deutsche Keramische Gesellschaft (FRG), 1205 pp. (1986)

A Design Review of Ceramic Components for Turbine Engines

This paper summarizes a program (AFML/APL Contract No. F33615-77-C-5171) to evaluate the application of ceramic materials in small, limited-life turbine engines. Advanced ceramics technology is employed in the program to achieve an affordable, reliable, high-performance capability for turbine engines in a missile application. The paper presents design and material considerations for ceramic rotor blades and stator vanes in addition to aerodynamic flow path analyses for ceramic components in high temperature environments. An iterative materials/design analysis was made with use of probabilistic design methods to predict the survivability of the ceramic components. Materials for both rotor blades and stator vanes were evaluated and selected based on mechanical and thermal stresses imposed by the optimum component design. A number of design concepts for the primary components are reviewed. These concepts include segmented-vane configurations and rotor airfoil shape and attachment schemes.