Study On Process And Mechanism Of Laser-high Temperature Chemical Composite Processing Of Silicon Carbide Ceramics

Ceramic materials are gradually applied to aerospace,precision machinery,microelectronics and other fields due to their excellent physical and chemical properties.At present,special processing technology is difficult to meet the needs of economical,high-precision,high-quality processing.In order to reduce production costs,improve processing quality,and integrate multiple technologies to achieve complementary advantages,it has attracted the attention of researchers at home and abroad.Laser processing has the advantages of high speed,high precision and no mechanical contact during processing;chemical processing does not produce thermal stress,and the quality is good.The new processing technology obtained by combining the two can remove thermal defects while completing efficient processing.Application prospects.However,there are many process parameters involved in composite processing,and the current combination of the two technologies is still in the exploration stage.In order to better grasp the processing technology and play the overall role of the composite,it is still necessary to conduct in-depth research on the correlation and synergy mechanism of the processing technology.Firstly,this paper analyzes the research status of precision machining technology for difficult-to-machine materials.On this basis,the reaction mechanism of laser ablation and high-temperature chemical processing of silicon carbide ceramics is studied.The influence of process parameters of corrosion-processed silicon carbide ceramics on processing quality is discussed.Correlated performance characterization of the corroded processed materials.The results show that with the increase of temperature and concentration of corrosive liquid,the corrosion rate of the material is accelerated.When the corrosive liquid is heated to boiling,the corrosion effect is obviously improved;When the solute mass fraction is 30% and the processing temperature is 120 °C,the roughness of the corrosion sample is the smallest,the length of the profile support is increased,and the surface quality is the best;if the corrosion temperature is too high or the time is too long,the grain will fall off.This leads to a significant drop in surface quality.In addition,compared with the machinedsamples,the samples after high-temperature chemical processing did not show cracks,and the surface was cleaned without reaction.Secondly,the processing properties of silicon aluminide ceramics by laser ablation,laser processing chemical post-treatment and laser high-temperature chemical compounding were studied.The effects of various processing methods on processing depth and surface quality were compared.The results show that in the laser processing process,the static chemical liquid processing is prone to cavitation,resulting in unstable liquid level,breakage point in the processing groove,and poor processing quality.The introduction of chemical liquid by low-pressure jet method can avoid vacuolization.At the same time,the effect of removing the thermal defects at high temperature is achieved.The surface of the groove after processing has no oxide layer and the inner wall has no recast layer,and the processing time is short,the processing process is simple,and there is no need for secondary clamping.Thirdly,the influence of laser process parameters on the microstructure of the grooved surface of silicon carbide surface was studied.The effects of laser power,scanning speed and repetition frequency on the contour of the composite machining tank and the positional roughness of the groove cut,inner wall and bottom are analyzed.The results show that increasing the power within a certain range and reducing the scanning speed can effectively increase the laser energy per unit time,increase the groove depth,and reduce the section taper.If the laser energy is too high,the structure of the tank may be damaged.Properly reducing the power and increasing the scanning speed will improve the flatness of the groove contour and reduce the roughness of the bottom and inner wall of the tank.The repetition frequency is related to the lap rate and the single pulse peak power.When the pulse width is constant,the roughness of each position of the groove increases first and then increases with the frequency.Finally,the interaction between laser processing and chemical processing in the composite milling of silicon carbide micro-planes was studied.The orthogonal experimental method was used to analyze the influence of laser processing parametersand chemical processing parameters on the machining depth and the roughness of the machined surface in composite milling.The results show that the laser power has the greatest influence on the processing depth,and the laser frequency has the most significant influence on the roughness of the machined surface.The analysis of variance shows that the laser process parameters have a significant effect on the processing depth and the roughness of the machined surface.The solution concentration has an obvious effect on the roughness of the machined surface,and the chemical processing process has almost no effect on the processing depth.Analyze the composite processing mechanism.Laser high-temperature chemical compound processing uses laser processing as the main means of material removal.The chemical liquid achieves the purpose of improving the quality of the processed surface by etching away the molten and oxidized materials in the heating process under high temperature environment.