The application of plasma spray technology on aviation engine

The statistic that Luo Gong manages makes clear, before 1976, aviation has 60% in engine spare parts, because of wear away and discarding as useless. After using wear-resisting coating, discard as useless rate fall to 33% , the effect is very distinct. For example, the appearance of damp protruding stage of lamina of titanium alloy compressor (about 0.

4cm2) gets of high load capacity bump and small brace up wear away. By dry titanium alloy not wear-resisting, life only 100h, and in the spray on protruding stage 0.

After the carbonization tungsten coating with thick 25mm, blade life is lengthened. The watch is shown 1 times for coating of caustic of commonly used wear-resisting. 2. Seal severe coating aviation to light gas turbine engine to wholer gas region seals tight system. System by interpose at axis, beat brief, variable blade apex, compressor and turbine various 60 place seal the 40 ～ between severe device composition, the stand or fall that seals severe device affects the power of engine, thrust and efficiency directly. Like turbine outer shroud (namely apex bottom clearance) seal course of study, press design demand, every increase the specific value of apex clearance and blade length 1% , turbine efficiency loss increases 1% ～ 3% . Visible, gas district is sealed fathering is one of important ways that improve efficiency and performance. For this, often use on the design but wear and tear seals severe coating to achieve gas district to seal tight end. Thermal spraying seals severe coating cent to be two kinds big, namely active grinding coating and but coating of wear and tear (passive) . (Coating of 1) active grinding (abrasive) it is hard commonly fight wear away gray alumina coating, spray is sealing tine of severe comb with a double-edged fine-toothed comb to go up. Rotate as the high speed of rotor, sealed like the grinding is as corresponding as its metal beehive like emery wheel group, make itself does not suffer as far as possible wear away. This asks coat tie strength is high, hardness is tall, heat proof quality is good. (2) can be ground coating of requirement of coating of wear and tear is soft and easily, have embellish short for Weihe River " function, anti-impact properties, heatproof brace up function, and have good combinative performance with matrix. Express the 2 coating that use to recommend. 3. Heat barrier coating now, the development trend of aviation turbine engine is big thrust, efficient, low oily cost and macrobian life. Raise the temperature burning gas of turbine entrance only, the pressure boost that just offers tall compressor possibly is compared and flow-rate ratio, raise the thrust of engine thereby, reduce oily cost. To satisfy the requirement of the turbine inlet temperature that raises ceaselessly, developing new-style alloy and cooling technology further while, should develop high temperature to defend energetically coating technology. A lot of advanced countries technology of coating of heat barrier of development of try to be the first. The basic tentative idea of heat barrier coating is to use the damage of high temperature resistant, anti-corrosive, wear-resisting with good stuff of pottery and porcelain and adiabatic property, make its are united in wedlock with the form of coating and alloy matrix, raise metallic structural member to fight the ability of high temperature corrosion environment thereby. To improve the physical consistence of coating and matrix, one metal is added to stick a layer between matrix and coating of pottery and porcelain, what and be raise coating of pottery and porcelain is heatproof brace up quality, mix cermet of its make it layer or cermet sometimes multilayer and compound layer. Felt layer is normally 0.

1 ～ 0.

Aluminium of the nickel chromium with thick 2mm, nickel, nickel chromic aluminium and MCrAIY alloy, among them M delegate Co, Ni or CoNi, al is to generate what what alumina covering layer needs, cr can be promoted generate AI2O3 and rise heatproof corrode ability, y can increase the combinative strength of the combinative strength between AI2O3 and MCrAIY and coating and matrix. Coating of heat barrier of turbine lamina use pottery and porcelain is a when improve engine performance important way, because of 0.

The alumina coating with thick 4mm can make temperature of surface of high temperature alloy reduces 100 ～ 300 ℃ . When engine full load, actual measurement turbine imports temperature burning gas to be 1370 ℃ , coating surface temperature is 1080 ℃ , blade metal temperature is 930 ℃ , saved what cooling air measures to use up greatly at the same time, improved turbine efficiency. The data makes clear, spray of surface of lamina of one class turbine 0.

The coating of heat barrier of pottery and porcelain with thick 25mm, but refrigerative air flow decreases 50% , the bad news that compare oil is improved 1.

3% , blade life raises 4 times. Till 1995, the total sales of coating of whole world pottery and porcelain amounts to above of 3 billion dollar, among them aviation engine applies year of average growth 28% . 3, the expectation of plasma spray technology 1. The amplification that uses range is used in the numerous craft of preparation TBCs at present, only plasma spray and EB-PVD technology have economic value most. In domain of technology of domestic aviation engine, the craft of coating of heat barrier of plasma spray preparation has directed application succeeds on the spare parts such as blade and heat shield in the turbine of some new-style aviation engine, won first prize of national defence science and technology. But the structure of attrib wattle shape that has a typical case as a result of plasma spray coating, bring about heat engine exhaustion easily, make coating easy come off invalidation, accordingly the coating of preparation of this kind of craft can be used at dormant workpiece only. And turbine job lamina bears not only high temperature and cold heat are handed in change, bear even the load that high speed movement brings, have EB-PVD technology preparation only have columnar coating of crystal structure TBCs, the use of lamina of job of OK and contented turbine asks. As develop quickly in succession in recent years those who rise exceed the spray technology such as firm plasma of spray of plasma of velocity of sound, low-pressure plasma spray and water, improved the quality of plasma spray further, enlarged the applied domain of plasma spray. Believe, sooner or later plasma spray technology can come with superior performance fill applies the blank that go up in engine. 2. The quality of preparation process assures at present, plasma spray technology already tended extraordinary stability and mature phase, but the advanced aviation technology of increasingly rapid development, also raised taller requirement to product quality. So the quality that how assure product of aviation engine coating with accurate and reliable means? Accompanying the development of plasma spray technology, emerge as the times require a kind " online detect equipment " , it is to install a kind of high speed on spray gun to photograph resemble device, the monitoring effect of real time, real value has to each parameter in plasma spray process, like electric current, voltage, blaze the temperature of each area distributings, the speed of pulverous particle, discharge and fused condition, this can all-around the quality of parameter of the coating in process of ground safeguard production. Additional, use online detect the actual spray parameter that equipment record comes down and coating function union rise analysis, choose the time of spray parameter with respect to greatly can managing actor, the effect that get twice the result with half the effort goes to since the central Shaanxi plain is studied in scientific research. 3. Process essence is refined in respect of plasma spray equipment, to use gas constitution to measure flowmeter operation of numerical control of control, clean energy control, manipulator and automatic metage numerical control send the direction such as pink to improve; Detect in the process respect, use coating ply and stress online nondestructive detects the effective control that waits for measure to realize a process. Through beginning blaze to shed duration to detect ply of monitoring, coating is mixed stress is online nondestructive detects, and the automation that implements thermal spraying operation and digitlization control, in order to assure the dependability of coating quality and repeatability. Anyhow, accompanying the further progress of plasma spray technology and system of relevant form a complete set, plasma spray technology will receive wider application in product of aviation engine coating. CNC Milling