Phosphate Fasteners and Applications
Phosphate fasteners are a type of hardware that utilizes a conversion coating to enhance the performance of the base metal. This blog post dives into the world of phosphate fasteners, exploring the coating process, applications, advantages and disadvantages, and provides specific examples of standard and special phosphate fasteners.
The Phosphate Coating Process
The phosphate coating, typically applied to steel fasteners, involves a multi-step chemical conversion process. Here's a simplified breakdown:
Preparation: The fastener undergoes cleaning to remove dirt, oil, and other contaminants.
Phosphate Bath: The fastener is submerged in a solution containing phosphates, typically zinc or manganese phosphates. An electric current may be used to facilitate the reaction.
Conversion: The phosphate solution reacts with the steel surface, forming a microcrystalline phosphate layer bonded to the base metal.
Rinsing: The fastener is rinsed to remove excess solution.
Optional: The fastener may be further treated with a lubricant or sealant for additional protection.
Standard Phosphate Fasteners
Standard phosphate fasteners are the most common type and are generally used in non-critical applications where corrosion resistance and improved paintability are desired.
Applications:
Woodworking: Phosphate-coated screws are popular for use in cabinets, furniture, trim, and other woodworking projects. The coating offers mild corrosion resistance and a good surface for paint adhesion. They come in various sizes, drive types, and thread styles, including:
Phillips flat head wood screws
Commonly used for pocket hole joinery due to the flat head Image of Phillips flat head wood screws phosphate.
Size: Typically #4 to #10, Length: 1/2" to 3"
Bugle head drywall screws
Designed to fasten drywall to wood studs. The bugle head provides a self-countersinking action Image of Bugle head drywall screws phosphate.
Size: Typically #6 to #10, Length: 1" to 6"
Appliance Assembly: Phosphate-coated screws are used in some appliances due to their affordability and mild corrosion resistance.
Advantages:
Improved Corrosion Resistance: The phosphate coating offers better corrosion resistance than bare steel, especially when used with paint or other post-treatment applications.
Enhanced Paintability: The phosphate coating provides a slightly rough surface that improves the adhesion of paint and other finishes.
Affordability: Phosphate coating is a relatively inexpensive process, making phosphate fasteners cost-effective for many applications.
Disadvantages:
Limited Corrosion Resistance: Phosphate coating offers mild to moderate corrosion resistance and is not suitable for harsh environments.
Brittle Coating: The phosphate coating can be brittle and may chip or crack under high torque or impact.
Special Phosphate Fasteners
Special phosphate fasteners are designed for more demanding applications and often incorporate additional treatments or use alternative phosphate formulations.
Applications:
Automotive: High-performance phosphate coatings are used on some automotive parts, such as engine components and suspension parts, for improved wear resistance and corrosion protection. These fasteners may use manganese phosphate or other specialized phosphate formulations.
Aerospace: Specific phosphate coatings are used on aerospace fasteners due to their ability to withstand extreme temperatures and harsh environments.
Advantages:
Enhanced Corrosion Resistance: Special phosphate treatments offer superior corrosion resistance compared to standard phosphate coatings.
Improved Wear Resistance: Certain phosphate formulations can enhance the wear resistance of fasteners, making them suitable for high-friction applications.
High-Performance Applications: Specialty phosphate fasteners can meet the demanding requirements of the automotive and aerospace industries.
Disadvantages:
Higher Cost: Special phosphate treatments are more expensive than standard coatings, increasing the overall cost of the fastener.
Limited Availability: Specialty phosphate fasteners may not be readily available at all hardware stores and may require sourcing from industrial suppliers.
Examples of Special Phosphate Fasteners:
Zinc Phosphate with Organics (ZPO): A common high-performance coating used in automotive applications for its ability to improve wear resistance and corrosion protection.
Manganese Phosphate (Mn Phosphate): Provides excellent corrosion resistance and is used in some aerospace and military applications.
Sourcing phosphate fasteners and chemicals:
U.S. Fastener Import & Trading Company (USFITC) has established business relationships with a manufacturer of phosphate fasteners and chemicals in Taiwan, with plants in Taiwan and Vietnam for production and distribution. The manufacturer has more than 20 years of experience in the production of chemicals for metal surface phosphating treatment, and uses the highest quality raw materials for standardized manufacturing. It is ISO 9001:2015 certified.
Products include: anti-rust oil, neutralizer, lubricant, blackening agent, degreasing agent, surface conditioner, manganese phosphate film agent, and more.
Contact us to source phosphate manufacturing chemicals or phosphate fasteners for your facility.