Dissolution of Silicon in Metals

Andy and his group were having difficulty analyzing Si by dissolution when the concentration was above 1% using ICP. He asked if Paul could suggest some dissolution techniques for Si concentrations above 1% in metals, specifically without the use of HF.

Dear Andy,

Unfortunately, there is no way to dissolve more than 1% Si in metals without adding HF, although I wish there was. In your case there is a need for acids to bring about solution of the alloy metals. Otherwise you could use and oxidative fusion such as sodium peroxide. The use of an HF resistant introduction system should be considered since putting HF through a glass system will, at best, give significant Si signals above that from the sample.

For pure Si, the mixture that works well is 1:1:1 water/HF/Nitric. So long as your acid mix includes some water and HF, you should have no difficulty dissolving elemental Si.

Please feel free to call me if you have and additional questions or concerns.

Serving you in chemistry,

Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures & Fellow Chemist

DISCLAIMER: Advice offered by the chemists at Inorganic Ventures is intended for the individual posing the question. Feel free to contact us to verify whether these suggestions apply to your unique circumstances.