High-Quality Passivation Services with a Quick Turnaround
Passivation is one of several metal finishing services Aero TMF provides for the aerospace, defense, and medical industries.
We offer many types of this popular precision metal surface treatment to protect parts from corrosion and enhance durability.
If you’re looking for reliability, quality, and rapid turnaround times, make Aero TMF your go-to partner for passivation services.
What Is Passivation?
Passivation is a chemical process for stainless steel and other alloys that removes surface contaminants and improves corrosion resistance. This treatment is typically applied to parts after machining operations such as cutting, welding, and grinding. The three stages of passivation include cleaning, passivating, and testing.
Cleaning
First, a degreaser eliminates contaminants like dust and debris that may have accumulated on the part during precision machining.
Passivating
Next, an acid bath removes any free iron and allows a chromic oxide layer to form once the part is exposed to oxygen. This passive layer guards against rust.
Testing
Finally, a test is used to measure the effectiveness of the treatment. Common tests include:
Free iron
Salt spray
High humidity
Copper sulfate
Water immersion
Potassium ferricyanide-nitric acid
Benefits of Passivation
Passivation extends the life of a part by protecting against corrosion, contamination, and defects. The protective finish increases the material's oxide and rust resistance and decreases the need for maintenance.
Passivation is also an excellent way to prepare parts for dry lubrication. The finish reduces friction between parts that rub together and improves durability. Before dry lubrication, parts are usually sandblasted and then passivated.
Types of Passivation and Common Specifications
We offer two types of passivation at Aero TMF: nitric acid and nitric acid with sodium dichromate. The process we use depends on the specific application requirements and the properties of the material being treated.
Nitric acid
With nitric acid passivation, the tank contains 20-45% nitric acid by volume at 70-90 degrees Fahrenheit. The simple process requires fewer steps than nitric acid with sodium dichromate. Nitric acid passivation is typically used for medical parts at Aero TMF. We adhere to ASTM A967 (Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts).
Nitric acid with sodium dichromate
With nitric acid with sodium dichromate passivation, the tank contains 20-25% nitric acid by volume with 2-3% sodium dichromate at 120-130 degrees Fahrenheit. Commonly used for defense and aerospace metal finishing, this type of passivation is ideal when a thicker passive layer is required or when dealing with challenging alloys requiring higher corrosion protection. We adhere to AMS 2700 (Passivation of Corrosion Resistant Steels).
Why Work with Aero TMF for Passivation Services?
While other shops that provide passivation services must wire each part before dipping it into the acid bath, our team quickly moves parts of all sizes through our facility with our stainless steel racks and baskets. Our efficient workflow often enables you to get your parts within 1-2 days.
Aero TMF is also your one-stop shop for chemical processing, quality testing, surface preparation, and painting. With this range of services, you can save time and money by outsourcing all your required finishing processes to our California metal finishing shop.
Tell us about your project and request a quote for our metal processing services today.
