Final answer:
A mixed base grease is created by combining sodium and calcium bases, which helps to incorporate the advantages of both into one product, commonly used for lubrication in various applications.
Step-by-step explanation:
A mixed base grease is a lubricant made from a combination of two different types of thickener bases, which give it certain desirable properties from both bases. In the case of the options provided, the correct combination for a mixed base grease would be A) sodium and D) calcium.
- Sodium greases have good thermal resistance and water resistance properties.
- Calcium greases are known for their good water resistance and are generally used in low to medium speed bearings.
By combining these two, a grease can be formulated that leverages the strengths of both sodium and calcium greases, offering improved performance characteristics for a variety of applications.