Quartz thermal changes

Changes in thermal stability and mass due to the formation of CdS nanoparticles in LB films were examined [180]. The LB films were formed onto gold-coated quartz oscillators from monolayers of arachidic acid or nonacosa-10,12-diynoic acid on CdCH containing subphases. The films were exposed to H2S gas until the mass change indicated complete conversion of Cd to CdS. The thermal stability of the H2S-treated films was reduced, with significant mass loss initiating at 55°C, compared to minimal mass loss in the untreated films up to at least 80°C under mild vacuum. The average CdS-particle size... 

Fused reworked quartz is chosen as the material for the beam since it has the lowest coefficient of expansion of any material. The value of the coefficient is 0.0042 X 10 4 cm./cm./°C. If the temperature variation over the two halves of the beam is 1°C. the difference in length of the two halves will be four parts in ten million. Since a difference of temperature of 1°C. over the beam length is not to be expected in a thermally shielded system, changes in length of the balance beam can be made negligible. 

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