1、 Material selection: Balance between corrosion resistance and high temperature stability
The material of stainless steel high-pressure crucible needs to meet the requirements of corrosion resistance, high temperature stability, and chemical inertness at the same time. It is recommended to choose high nickel low-carbon stainless steel (such as 316L or X2CrNiMo18143), which has a high nickel content (10% -14%) and a low carbon content (≤ 0.03%), and can effectively resist oxidative acid and chloride corrosion while maintaining structural stability at high temperatures. If the melted material contains highly corrosive components (such as high concentration acids or salts), a gold-plated stainless steel crucible can be considered. The sample and substrate are isolated by a 5 μ m gold coating to avoid side reactions, but the cost is high and suitable for high-precision experiments or special material melting.
2、 Volume matching: precise adaptation of sample size to testing requirements
The selection of volume should take into account the sample size, thermal effect intensity, and resolution requirements. Small volume crucibles (such as 25 μ L) have small signal time constants and low thermal hysteresis, making them suitable for testing trace samples (<1mg) or weak thermal effects (such as high-energy material decomposition); A large volume crucible (such as 100 μ L or 160 μ L) can accommodate more samples (5-10mg), enhance the strength of the test signal, and is suitable for polymer melting or composite material analysis. Please note that the sample size should not exceed 1/3 to 1/2 of the crucible volume to avoid overflow or uneven heat distribution.
3、 Pressure Level: Targeted Selection of Safety Threshold and Experimental Scenarios
The pressure level should be determined based on the decomposition characteristics of the sample and experimental safety requirements. Low pressure crucible (pressure resistance<0.3MPa) is suitable for conventional thermal analysis (such as specific heat capacity and oxidation induction period testing); Medium pressure crucible (pressure resistance 2MPa) is used for samples with significant water loss, such as biological samples or drugs; The high-pressure crucible (with a pressure resistance of 15MPa) is designed specifically for volatile or highly active materials (such as strong or high-energy metals), which can suppress vaporization heat interference and ensure safe testing in a sealed environment. If pursuing test repeatability, it is recommended to choose disposable high-pressure crucibles to avoid cleaning residues or decreased sealing caused by repeated use.