COMPREHENSIVE THERMAL ANALYSIS OF FLUX, BETULINOL DIPHTHALATE, FOR SURFACE MOUNTING TECHNOLOGY
This article is devoted to the complex thermal analysis of flux, betulinol diphthalate, for stencil and solder pastes used in thick-film and thick-film surface mount technologies. Comprehensive thermal analysis established that the decomposition of betulinol diphthalate in an argon atmosphere and in air proceeds in two stages in the temperature range 165-460 °C. It is shown that the mechanism of decomposition of the flux in an oxidizing and inert atmosphere is different, the ongoing oxidative processes inhibit the process of complete decomposition of the structure of betulinol diphthalate Differential scanning calorimetry and thermogravimetry established that when betulinol diphthalate is heated in an inert atmosphere of argon in the temperature range 165-460 °С loss of 96.5 % of the original mass, and in the oxidizing one - 79.6 %. Stepwise decrease in the mass of the flux in the temperature range: in air 165-215 °С - 19.3 %, 215-355 °С - 25.4 %, 355-390 °С - 26.3 %; in an argon atmosphere: 165-285 °С - 24.9 %, 285-355 °С - 17.0 %, 355-465 °С - 54.3 % indicates a fairly wide range of fluxing activity of betulinol diphthalate. The wide range of chemical activity of betulinol diphthalate makes it possible to use it in stencil and solder pastes with different reflow temperatures.