REACTIVE MECHANISMS OF PYROLYSIS OF STEREOLITHOGRAPHY PROTOTYPE FOR
PREPARATION OF CARBON TEMPLATE

CUI Zhizhong^{1, 2}  LI Dichen¹  LI Jishun³  DUAN Yugang¹

(1. State Key Laboratory of Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049;

 2. Key Laboratory of Advanced Manufacturing Technology in University of Henan Province,

Henan University of Science and Technology, Luoyang 471003;

3. Key Laboratory of Modern Design and Transmis-sion System of Henan Province,

Henan University of Science and Technology, Luoyang 471003 )

Abstract: A novel process for fabricating complex-shaped silicon carbide ceramic parts based on the stereolithography (SL) prototyping technology is presented. Carbon template is fabricated by pyrolysis of SL prototype at a heating rate of 20 ℃/min from room temperature to 800 ℃ and then hold 30 min under vacuum. The identification of volatile components derived from pyrolysis of photo-curable resin is investigated by pyrolysis / Fourier transforms infrared spectrometer (Py/FTIR). The elements identification and chemical bond analysis of the pyrolyzate of photo-curable resin are studied by X-ray photoelectron spectrometer (XPS) and FTIR respectively. The morphology of the carbon template is analyzed by scanning electron micro-scope (SEM). Open porosity of the carbon templates are measured by Archimedes principle. The results show that the pyrolysis reaction is a condensation polymerization process in which low molecular weight paraffin hydrocarbon, CO2 and aldehyde are produced and escape in gaseity. So a little carbon is lost. The pyrolyzates are porous carbonaceous materials that contain a little H and O. The open porosity is 42% and increases with the heating rate. The residual carbon mass fraction of SL proto-type is 10%. The bending strength of the carbon template is 22 MPa that is sufficient for the requirement of infiltration of Si.

Key words: Stereolithography prototype Pyrolysis Carbon template Fourier transforms infrared spectrometer

CLC No: TB332

国家自然科学基金资助项目(50475082). Received 20060408,  received in revised form 20061101