The project mainly focuses on tooth-shape memorial alloy austenite transformation temperature mea...

Start Date

2009

End Date

2011

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Development of CRMs for Austenite Transformation Temperature of Tooth Shape Memorial Alloy

The project mainly focuses on tooth-shape memorial alloy austenite transformation temperature measurement standard for dental research. It aims to provide correlation detection method and authoritative technical support, ensure that the relevant characteristics of value traceability and dissemination enhance dental-related detecting ability and guarantee the measurement result is accurate, reliable.

 

Tooth shape memory alloy with its unique shape memory effect and super elastic properties is widely used in clinical oral orthodontic treatment. Because the austenite transformation temperature of the material is very sensitive to alloy composition, heat treatment and material processing technology, so the measurement value of austenite transformation temperature becomes important guidance for products detection and manufacture. ISO standards and Chinese standards stipulate thermal analysis to be the method for austenite transformation temperature measurement. However, thermal analysis in this measurement range lacks standard substance so it can’t guarantee the measurement accuracy for this material. In addition, determination of the austenite transformation temperature needs a perfect standard to ensure that the determined value is correct.

Taking account of the above requirements, the project obtained the following results:

1) It has developed two thermal analysis certified reference materials (CRMs). The temperature uncertainty and heat uncertainty of gallium standard material are 0.20℃(k=2) and 0.48J/g (k=2), respectively; temperature and heat uncertainties of phenyl salicylate standard material are 0.34℃(k=2) and 0.62J/g (k=2), respectively. Two kinds of low-temperature thermal analysis standard reference material has filled the blank in (0~100)℃thermal analysis standard substances blank.

2) It has researched on a method for tooth shape memory alloy phase change temperature measuring by differential scanning calorimeter (DSC) technique. It has developed a dental transformation temperature of shape memory alloys standard substance, whose property values include initial austenite temperature (As), austenite finish temperature (Af), Martensite start temperature (Ms) Martensite end temperature (Mf). The measurement uncertainties of the above values are 1.02℃(k=2),1.26℃(k=2),1.18℃(k=2)and 1.12℃(k=2), respectively. It is the first time a CRM of this type has been developed and it has filled the blank in this field for China.

3) It has completed a revision work for verification regulation for differential scanning calorimeter (DSC) calibration. It is evaluated and concluded by National Physical Chemistry Council.

4)One practical patent is authorized to be used by manufacturer, and another patent is unveiled to public..

5) 1 paper has been published in one of Chinese core journals of scientific & technological research.