不锈钢连接用改性磷酸盐粘接剂的制备及界面反应机理

Preparation of Modified Phosphate Adhesive for Connection of Stainless Steel and Its Interface Reaction Mechanism

为了提升磷酸盐胶黏剂的耐高温性能,以自制的磷酸二氢铝为基体,纳米Al_(2)O_(3)、Si粉和低温熔融玻璃粉(Zn–B–Si–Al–R)等为填料,制备出一种新型磷酸盐粘结剂,并对其界面反应机理进行了分析.结果表明:当Fe_(2)O_(3)、ZrO_(2)、CuO的添加量分别为5%、10%、15%(质量分数)时,粘结剂在500℃的高温拉伸强度为5.28 MPa,质量损失率仅为7.8%.从室温至500℃,粘结剂与不锈钢基体热膨胀系数匹配良好,两者的差值始终小于1.5×10^(–6)K^(–1).同时,电势差异促进了Fe与Cu的离子交换,在界面处形成成分梯度层,有效缓解因热失配而产生的热应力,提高粘结剂在高温下的粘结强度.

A novel phosphate binder was prepared with homemade aluminum dihydrogen phosphate as a matrix and nano-Al,O3,Si powder and low-temperature fused glass powder(Zn-B-Si-Al-R)as fillers to enhance the high-temperature resistance of phosphate adhesives.The interface reaction mechanism was analyzed.The results show that the high-temperature tensile strength of the adhesive is 5.28 MPa at 500 C,and the mass loss is only 7.8%when the additions of Fe_(2)O_(3)、ZrO_(2)and Cu0 are 5%(in mass),10%and 15%,respectively.From room temperature to 500 C,the coefficient of thermal expansion of the adhesive matches well with the stainless steel substrate,and the difference is less than 1.5x10^(-6)k^(-l).Meanwhile,the discrepancy of electric potentials promotes the ions exchange of Fe and Cu,forming the composition gradient layer at the interface,which effectively relieves the thermal stress caused by thermal mismatch and improves the bond strength of the adhesive at a high temperature.