Sample Preparation and Requirements for Nanoindentation/Scratch Testing

Sample Preparation

1. Sample Types

Nanoindentation/scratch testing typically targets different types of materials, including thin films, coatings, and bulk materials. For thin film materials, they need to be prepared with a certain thickness, ensuring flatness and surface quality. For bulk materials, they should be processed into specified dimensions, such as cylinders or blocks.

2. Preparation Methods

Thin film preparation methods include Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), and others. Bulk material preparation methods include mechanical processing, molten salt electrolysis, powder metallurgy, and more.

3. Preparation Process

During the sample preparation process, the following points should be noted:

(1) Ensure the purity and uniformity of the sample to avoid the influence of impurities and defects on the test results;

(2) Control the thickness and dimensions of the sample to meet the requirements of the testing equipment;

(3) Avoid damaging the sample during preparation, such as scratches or cracks;

(4) For thin film samples, surface finishing should be performed after preparation to improve bonding strength.

Sample Requirements

1. Surface Quality

Nanoindentation/scratch testing requires a certain level of surface flatness, with minimal roughness. For thin film samples, surface roughness should be less than 10 nanometers. For bulk samples, surface roughness should be less than 1 micrometer.

2. Size Requirements

Sample dimensions should meet the requirements of the testing equipment. Generally, the diameter or width of the sample should be between a few millimeters to several tens of millimeters, and the height or thickness should range from tens of nanometers to several micrometers.

3. Bonding Strength

During sample preparation, ensure that the bonding strength is high enough to prevent detachment or damage during testing.

4. Hardness Requirements

Nanoindentation/scratch testing is suitable for materials with various hardness levels. For harder materials, such as metals and ceramics, a diamond indenter should be used. For softer materials, such as plastics and rubbers, a sapphire indenter is required.

5. Sample Quantity

To enhance the reliability of test results, multiple samples usually need to be tested. The number of samples should be determined based on the uniformity of the material and the precision of the testing equipment.

6. Sample Storage

Before testing, samples should be properly stored to avoid environmental influences such as temperature, humidity, and light.