Question

1. the surfacing method that sprays high - temperature material onto a surface is called ______.
2. what cleaning method is generally used on aluminium?

Explanation:

1. For question 3: This is a common industrial surfacing technique where molten or high-temperature material is atomized and sprayed onto a substrate to create a protective or functional coating.
2. For question 4: This is a standard cleaning process for aluminum that uses an acidic or alkaline solution to remove contaminants, oxide layers, and prepare the surface for further treatment.

Answer:

1. Thermal spraying
2. Chemical cleaning (or acid washing/alkaline cleaning; chemical cleaning is the general, widely used term)