SEMI C92 - Test Method for Determining the Critical Pitting Temperature of Stainless Steel Surfaces Used in Corrosive Gas Systems by Use of a Ferric Chloride Solution
This Standard was technically approved by the Gases Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on December 4, 2015. Available at www.semiviews.org and www.semi.org in February 2016.
The purpose of this Test Method is to determine the relative resistance to pitting corrosion of the wetted surfaces of components intended for use in corrosive gas distribution systems for semiconductor manufacturing. This Test Method is an adaptation of ASTM G48 and is intended to differentiate between stainless steels of differing compositions or processing that may affect the corrosion performance of the wetted surfaces. Detailed information on the method is found in ASTM G48.
This Test Method describes a procedure which may be used to rank the pitting corrosion resistance of wetted surfaces of tubing or components of finished surfaces intended for use in corrosive gas systems. Pitting corrosion is a potential corrosion failure mechanism in semiconductor gas delivery systems, particularly in welded components or tubing exposed to corrosive gases with moisture present.
This Test Method is an adaptation of ASTM G48 Method E, Critical Pitting Temperature Test for Stainless Steel. The adaptation describes a method for performing the Test Method on coupons or wetted surface sections cut from gas supply system components or tubing. It is an aqueous immersion method in an acidified ferric chloride solution.
This Test Method is reproducible and provides a metric (i.e., critical pitting temperature) in addition to a qualitative (i.e., visual) evaluation of corrosion resistance.
Referenced SEMI Standards
SEMI F19 — Specification for the Surface Condition of the Wetted Surfaces of Stainless Steel Components