Why take a salt spray test 1. In order to verify that the metal parts on the product will not corrode when exposed to the atmosphere or other environments. The product can be placed in the use environment for a long enough time, such as one life cycle of the product. This is time-consuming and laborious, in practice is rarely used. Thus, a convenient method is needed to evaluate the corrosion resistance of products. Salt spray test is an accelerated anti-corrosion evaluation method of artificial atmosphere. It atomizes a certain concentration of salt water, and then sprays it in a closed incubator, and observes the change of the tested sample after being placed in the box for a period of time. It reflects the corrosion resistance of the tested sample. It is an accelerated test method, that is, it takes a short time, not a few years, but only a few days or even a few hours. Although the salt spray test is an effective test method. However, due to many factors affecting corrosion, a single resistance to salt spray cannot be used as a representative of the performance against other media, so the results of the salt spray test cannot be used as the test material in all environments. A direct guide to corrosion performance. Also, the performance of materials in test should not be used as a direct guide to corrosion resistance in service. Nevertheless, the salt spray test method can still be used as a method for testing the tested materials.

2. Which products need to be tested by salt spray metals and their alloys metal cover organic overlay Anodized film 3. Covering layer 1) Cover type Organic coating, such as paint, varnish, powder coating (powder), anti-rust oil, etc. Metal coating, such as electroplating, electroless plating, ion plating, sputtering, hot dip plating, chemical vapor deposition, etc. Commonly used electroplating layers are galvanized, copper-plated, nickel-plated, chrome-plated, tin-plated and brass-plated, lead-tin alloy and so on. 2) The role of the covering layer Aesthetics Example: Bright chrome plating Protects...

PH value is 6.5~7.2 The temperature in the test chamber is 35 ± 2°C (US 35+1.1/-1.7 °C) The sedimentation velocity of salt spray is 1.5±0.5mL per 80cm² per hour Sample preparation The type, quantity, shape and size of the sample shall be determined according to the product standard. If there is no standard, it shall be negotiated by the relevant parties. Before the test, the sample must be cleaned by an appropriate method, but the protective organic film intentionally coated on the sample should not be washed away. For cut specimens, the cut area should be protected with paint, paraffin or tape....

Some proper nouns explained Anodic coating: refers to the coating in which the coating is anodic to the substrate. That is, the coating is more active than the base metal, and if an electrochemical reaction occurs, the coating will corrode first. For example, galvanizing on steel, etc. Cathodic coating: refers to the coating that the coating is cathodic to the substrate. That is, the coating is not as active as the base metal. If an electrochemical reaction occurs, the base metal will corrode first. For example, tin plating on steel, etc. ASTM D610-01 The evaluation result generally consists...

ISO 4628-3:2003 The evaluation result is Ri followed by an Arabic numeral, such as Ri6, Ri4. Numbers indicate corrosion area The corresponding relationship between the number and the corrosion area is as follows: Number of ratings Corrosion area Ri 0 0 Ri 1 0.05 Ri 2 0.5 Ri 3 1 Ri 4 8 Ri 5 40/50 ISO 10289:1999 The evaluation result is generally composed of the protection rating number (Rp) and the appearance rating number (RA), if only the protection rating is required. Appearance ratings can be omitted. The protection rating number (Rp) indicates the ability of the coating to protect the base...

damage area of the coating. The lowercase letters represent the subjective evaluation of the degree of damage to the coating, and the uppercase letters represent the type of damage to the coating. (Rp, Ra explained R=Rating p = protection a = appearance) The corresponding relationship between the number and the corrosion area, as shown below: Subjective evaluation of cover damage degree vs = very mild s = mild m = moderate x = severe Classification of Overlay Damage Types A Spotting and/or color change due to cover failure B Darkness caused by corrosion of the cover layer that is hard to see...

Rating example 2 0.3% of the area on the specimen showed base metal corrosion Rp = 7 The corrosion products of the anodic coating cover 0.15% of the total area, and the area with slight bubbling of the top electrodeposited layer exceeds 0.75% of the total area Ra = 8 vs C, 6 mG Rating legend: