Ceramic microthrusters with an embedded Pt resistive heater,two temperature sensors,and a Pt or Ag catalytic bed were made of high-temperature co-fired alumina ceramics.To increase the surface area by a factor of 1.21...Ceramic microthrusters with an embedded Pt resistive heater,two temperature sensors,and a Pt or Ag catalytic bed were made of high-temperature co-fired alumina ceramics.To increase the surface area by a factor of 1.21,and so the catalytic effect,the Pt catalytic bed was made porous by mixing the Pt paste with 15—20vol.%graphite sacrificial paste before screen printing it.Ag was in-situ electroplated on the porous Pt surface after sintering.Decomposition of 50wt.%hydrogen peroxide as a monopropellant was studied both qualitatively and quantitatively by changing the catalyst(between Ag and Pt),flow rate(15—55 μl/min),and operating temperature(115—300℃).A reference device without catalyst exhibited an unstable behavior as a result of no,or vety little,decomposition,whereas the Ag catalyst was more stable,and the Pt one even more stable.Also,Pt was found to be slightly more effective.Quantitatively,there were small differences between Pt and Ag in the power needed to maintain the temperature.The inventive methods to make the Pt bed porous as well as in-situ electroplating Ag were success-fully demonstrated.展开更多
基金The Swedish National Space Board and the Centre for Natural Disasters Science(CNDS)are acknowledged forproject fundingThe Knut and A lice Wallenberg Foundation is acknowledged for funding the laboratory facilitiesPeter Sturesson at the Department of Engineering Sciences,Uppsala University is gratefully thanked for help with the SEM.Dhananjay V.Barbade,who participated in the previous study,is appreciated for inspiration to this work.
文摘Ceramic microthrusters with an embedded Pt resistive heater,two temperature sensors,and a Pt or Ag catalytic bed were made of high-temperature co-fired alumina ceramics.To increase the surface area by a factor of 1.21,and so the catalytic effect,the Pt catalytic bed was made porous by mixing the Pt paste with 15—20vol.%graphite sacrificial paste before screen printing it.Ag was in-situ electroplated on the porous Pt surface after sintering.Decomposition of 50wt.%hydrogen peroxide as a monopropellant was studied both qualitatively and quantitatively by changing the catalyst(between Ag and Pt),flow rate(15—55 μl/min),and operating temperature(115—300℃).A reference device without catalyst exhibited an unstable behavior as a result of no,or vety little,decomposition,whereas the Ag catalyst was more stable,and the Pt one even more stable.Also,Pt was found to be slightly more effective.Quantitatively,there were small differences between Pt and Ag in the power needed to maintain the temperature.The inventive methods to make the Pt bed porous as well as in-situ electroplating Ag were success-fully demonstrated.
