Explanation: The refractories are called the heat resistant materials as they can withstand high temperatures without being fused. This is an important property used in design of patterns.

Explanation: Hematite is an iron ore. It can only be used after extracting the iron from it. Direct application is not permitted.

Explanation: The Chlorine here is a gaseous flux. It is used to remove the dissolved hydrogen and entrapped dross. The entrapped dross is not present in the magnesium alloys.

Explanation: The tensile strength of aluminum is very low. This makes it non-suitable for the pattern making applications.

Explanation: Zinc shows lack of dimensional stability under the aging condition and is susceptible to intergranular corrosion. Hence it cannot be used widely in foundry applications.

Explanation: Silicon is used in the form of Silicon dioxide as it has the ability to resist oxidation in steel. Hence it is termed as the best deoxidizer.

Explanation: Titanium has no effect on the hardening ability and it inhibits grain growth. Hence the titanium has highest carbide forming tendency.

Explanation: The straight grained and properly seasoned wood such as Mahogany, Teak, Deodar etc., are free from knots and are easy to work with. There are very few defects in casting when worked with these patterns.

Explanation: Aluminium has long durability, excellent resistance to corrosion. Hence, aluminium is usually referred to as the best pattern material.

Explanation: Wax Patterns provide good surface finish and impart high accuracy. Hence, they have great use in the Investment Casting Process.