Correa Osvaldo, de Abreu Filho Pompeu Pereira, Moshkalev Stanislav, Swart Jacobus
Faculty of Electrical Engineering and Computing-FEEC, University of Campinas, Campinas 13083-852, SP, Brazil.
Center for Semiconductor Components and Nanotechnologies-CCSNano, University of Campinas, Campinas 13083-870, SP, Brazil.
Sensors (Basel). 2022 Apr 24;22(9):3256. doi: 10.3390/s22093256.
A new Pb-free glass containing several oxides (BiO, BO, SiO, AlO and ZnO) with sintering temperature reduced down to 600 °C has been developed for applications in a piezoresistive pressure sensor. Using this low sintering temperature glass, it was possible to fabricate micrographite-based pastes and piezoresistive films without losses of graphitic material during the sintering. Good adherence of the films onto alumina substrates was observed and attributed in part to the reactions of ZnO and BiO with alumina substrates. Piezoresistive films with uniformly distributed micrographite particles were produced using sodium carboxymethyl cellulose (NaCMC) in aqueous solutions during the preparation of pastes. NaCMC plays a decisive role in interactions between micrographite particles and glassy matrix, providing good wettability of glass powder particles and homogeneous distribution of MG particles in the pastes. Finally, excellent repeatability of the sensor response to the applied deformations was verified in cycling experiments when the sample was submitted to 1000 load/release cycles. These results demonstrated very high stability of the sensor response (within ±1%), and also evidenced high stability of the film under the cyclic strain loads and good film adherence to the substrate.
一种含有多种氧化物（BiO、BO、SiO、AlO和ZnO）的新型无铅玻璃已被开发出来，其烧结温度降至600°C，用于压阻式压力传感器。使用这种低烧结温度玻璃，可以制造基于微石墨的浆料和压阻薄膜，且在烧结过程中不会损失石墨材料。观察到薄膜与氧化铝基板有良好的附着力，部分原因是ZnO和BiO与氧化铝基板发生了反应。在制备浆料过程中，使用羧甲基纤维素钠（NaCMC）的水溶液制备出了微石墨颗粒均匀分布的压阻薄膜。NaCMC在微石墨颗粒与玻璃基体之间的相互作用中起决定性作用，使玻璃粉末颗粒具有良好的润湿性，并使微石墨颗粒在浆料中均匀分布。最后，在循环实验中，当样品经受1000次加载/释放循环时，验证了传感器对施加变形的响应具有出色的重复性。这些结果表明传感器响应具有非常高的稳定性（在±1%以内），也证明了薄膜在循环应变载荷下具有高稳定性以及薄膜与基板之间有良好的附着力。
