IS 3972 : Part 2 : Sec 5 : 2020/ISO 28706-4 : 2016 Methods of Test for Vitreous Enamelware - Part 2 Test Methods - Section 5 Resistance to hot alkali

Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 2/Sec 5) (Second Revision), which is identical with ISO 28706-4 : 2016 ‘Vitreous and porcelain enamels — Determination of resistance to chemical corrosion — Part 1: Determination of resistance to chemical corrosion by alkaline liquids using a cylindrical vessel’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on recommendation of the Ceramicware Sectional Committee and approval of the Chemical Division Council.

This Standard(Part 2/Sec 5 of IS 3972) describes the test method for the determination of the resistance of vitreous and porcelain enamelled articles to attack by alkaline liquids at temperatures between 25°C and 95°C.

Corrosion of vitreous and porcelain enamels by aqueous solutions is a dissolution process. The main component of the enamel, SiO2, forms a three-dimensional silica network. After hydrolysis, it decomposes and forms silicic acid or silicates. These are released into the attacking medium. Other components, mainly metal oxides, are hydrolysed as well and form the corresponding hydrated metal ions or hydroxides. The most important parameters influencing aqueous corrosion of the enamel are the enamel quality, the temperature and the pH value. Inhibition effects resulting from the limited solubility of silica can also contribute.

This standard was originally published in 1968 and subsequently revised in 1988. During the first revision, IS 3972 was bifurcated and Part 2 of IS 3972 was further divided into 13 sections, each dealing with various test methods applicable to vitreous enamelware. In the first revision, Part 2/Sec 5 of IS 3972 was aligned with ISO 2745 : 1973 (without adoption), with modification in the method of test prescribed previously.

While reviewing IS 3972 (Part 2/Sec 5), the committee decided to revise it by adopting ISO 28706-4 : 2016, which has replaced ISO 2745.

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.