Fabrication of barium-strontium aluminosilicate coatings on C/SiC composites via laser cladding

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2017,（2）
• 页码范围: 166-171
• 页数: 6页
• 语种: 英文

摘要

Barium-strontium aluminosilicate (BSAS) and Si/BSAS coatings were fabricated on the surface of C/SiC composites via a two-step laser cladding process.The microstructure,mechanical properties,and the water vapor corrosion behavior of the samples were investigated.The BSAS coating was found to be tightly bonded to the substrate and only a few pores and micmcracks were observed.The introduction of a silicon middle layer was revealed to reduce thermal stress and promote the healing of defects formed during the laser cladding process.To evaluate the corrosion resistance,the BSAS and Si/BSAS-coated C/SiC composites were exposed to an atmosphere of 50％ H2O and 50％ O2 at 1250 ℃.The resulting weight change and flexural strength were measured as a function of the corrosion time.The addition of the silicon middle layer below the BSAS top layer resulted in a better resistance to water vapor corrosion.Furthermore,the Si/BSAS-coated samples showed a lower weight loss and a smaller reduction in flexural strength than the BSAS-coated and the uncoated samples during water vapor corrosion.Thus,laser cladding is demonstrated to be an effective and feasible method to fabricate high-quality ceramic coatings on C/SiC composites.The introduction of a silicon middle layer can inhibit defect formation during the laser cladding process and protect the composite from water vapor corrosion.