How to choose a salt spray machine that suits you?

Choosing the right salt spray machine requires comprehensive consideration. Dongguan Zhongzhi Times Testing Equipment Co., Ltd. offers some recommendations:

1. Choose the type based on test requirements:

• Neutral salt spray test: If you’re primarily testing the corrosion resistance of general metal materials and surface coatings under normal conditions, the neutral salt spray test is likely the most commonly used. This test uses a 5% sodium chloride solution with a pH adjusted to a neutral range (6-7). The test temperature is generally 35°C, making it suitable for corrosion testing of most common products. For example, this type of salt spray machine can be used for testing general hardware and coatings on building materials.
• Acidic salt spray test: For products used in acidic environments or potentially exposed to acidic substances, such as testing the resistance of automotive parts to acid rain, the acidic salt spray test is more appropriate. The acidic salt spray test involves adding glacial acetic acid to a 5% sodium chloride solution, making the solution acidic. This more corrosive solution can more quickly test a product’s corrosion resistance under acidic conditions.
• Copper Salt Accelerated Acetate Salt Spray Test: If you need to quickly assess a product’s corrosion resistance, or if the product’s operating environment requires high corrosion resistance, the copper salt accelerated acetate salt spray test is a good option. This test involves adding a small amount of copper salt (copper chloride) to a salt solution, strongly inducing corrosion. The corrosion rate is approximately eight times that of a neutral salt spray test, and the test temperature is 50°C. It is often used for products with high corrosion protection requirements, such as aerospace components and high-end electronic equipment.
• Alternating Salt Spray Test: If a product experiences a variety of environmental conditions in actual use, such as alternating dry and wet conditions and temperature fluctuations, an alternating salt spray test can more realistically simulate these conditions. This is a comprehensive salt spray test that combines different salt spray, dry, and wet phases to comprehensively evaluate a product’s durability and corrosion resistance.

1. Consider the characteristics of the test sample:

• Sample size: Select a salt spray machine of appropriate size based on the sample size. If the sample is small, a small salt spray tester can be selected. For example, a small tester with a test area of ​​approximately 600x450x400mm is suitable for small samples such as electronic components and hardware screws. If the sample is large or multiple samples need to be tested simultaneously, a large salt spray tester with a larger test area is required, which can accommodate large products or batch testing.
• Sample Weight: For heavier samples, consider the salt spray tester’s load capacity and sample placement convenience. Some salt spray testers have special designs, such as inclined-top salt spray testers, which are suitable for heavier samples and facilitate sample placement.
• Sample Shape and Placement: If the sample is irregularly shaped or requires placement at a specific angle, ensure that the salt spray tester’s test chamber has a suitable rack or fixture to accommodate the sample placement requirements. Generally, racks come in two types: V-shaped and round bar. The specimen should be placed at an angle of 15-30 degrees from the vertical.

1. Pay attention to the equipment’s performance parameters:

• Salt mist deposition: Salt mist deposition is a key indicator of salt spray machine performance. Ensure that the equipment’s salt mist deposition meets the national standard of 1-2 ml/80 cm²·h. The uniformity of salt mist deposition is also important; uniform salt mist deposition ensures the accuracy of test results.
• Temperature range and control accuracy: Different test types have different temperature requirements. Select a salt spray machine with an appropriate temperature range based on the test needs. Furthermore, the higher the temperature control accuracy, the better the repeatability and reliability of the test results. Generally speaking, a salt spray machine with a temperature control error within ±0.5°C performs well.
• Spray pattern and spray volume: Common spray patterns include continuous spray and periodic spray, which can be selected based on test requirements. The spray volume should be adjustable, and the nozzle should ensure uniform distribution of the salt mist to avoid excessive or insufficient localized corrosion.

1. Inspect the equipment’s material and structure:

• Cabinet material: The salt spray machine’s cabinet material should have good corrosion resistance and aging resistance. Common chamber materials include PVC and PP. PVC is relatively inexpensive and offers excellent corrosion resistance. PP offers superior temperature resistance and aging resistance, but is more expensive. If the test environment is highly corrosive or the accuracy of the test results is extremely critical, higher-grade materials such as titanium may be appropriate.
• Nozzle Material: The nozzle is a key component of the salt spray machine and requires corrosion-resistant, non-clogging materials. Nozzles made of special glass or high-quality stainless steel offer excellent performance, ensuring stable salt spray and long-term use.
• Sealing: A good seal prevents salt spray leakage, contaminating the laboratory environment and harming the health of operators. Check the seal between the salt spray machine lid and chamber, as well as the seals at locations such as the exhaust port.

1. Understand the equipment’s quality certifications and after-sales service:

• Quality Certification: Choose a salt spray machine that has passed third-party quality inspections to ensure its quality and performance meet relevant standards and requirements. For example, check whether the equipment has CE or ISO certification.
• After-sales service: Salt spray machines are long-term equipment, so after-sales service is crucial. Choose a manufacturer with excellent after-sales service who can provide timely repair, maintenance, and technical support to ensure the normal operation of the equipment. Understand the manufacturer’s after-sales service commitments, repair response speed, and spare parts availability.