회사 소식 Does Tungsten Carbide Contain Nickel?

If you work with tungsten carbide products—whether sourcing wear parts, specifying seal rings, or troubleshooting equipment—you might have asked: “Does tungsten carbide contain nickel?” The answer isn’t universal. Most standard industrial tungsten carbide does not contain nickel by default; it relies on cobalt as the main binder metal. However, nickel is often used in specialized tungsten carbide grades to meet specific needs, like corrosion resistance or low-temperature toughness. In this article, we’ll break down when tungsten carbide uses nickel, why it’s added, how it differs from cobalt-based grades, and key factors to consider when choosing between them. All information is grounded in real industrial experience, with no complex jargon—just practical insights you can apply to your work.

To understand if nickel is present, let’s start with the basic composition of tungsten carbide. It’s a composite material made of two core components:

1. Tungsten carbide crystals: The “hard” part of the material (Mohs hardness 8.5–9), responsible for wear resistance. These crystals can’t stand alone—they need a binder to hold them together.
2. Binder metal: The “tough” part that bonds the crystals, adding strength and preventing brittleness.

In standard tungsten carbide (used for 80% of industrial applications like drill bits, general wear liners, and pump seals), the binder is almost always cobalt. Nickel is not included here—cobalt is chosen because it balances cost, ease of manufacturing, and performance for most common tasks.

• Example: A standard tungsten carbide seal ring for freshwater pumps, or a carbide-tipped woodworking cutter—these will nearly always use cobalt as the binder, with no nickel.

Nickel is added to tungsten carbide only when the application demands properties that cobalt can’t provide. Here are the three most common reasons to use nickel-based tungsten carbide:

Cobalt is prone to corrosion in harsh chemical conditions—like acidic/alkaline solutions or saltwater. Nickel, by contrast, has strong corrosion resistance, making it ideal for these scenarios.

• Common applications:
  • Seal rings in chemical processing pumps (handling acids, alkalis, or solvents).
  • Wear parts in marine equipment (seawater exposure, like propeller shafts or offshore drill bits).
  • Liners in wastewater treatment plants (chlorinated or chemically treated water).
• Why it works: Nickel forms a thin, stable oxide layer on its surface that blocks further reaction with corrosive substances—something cobalt can’t do as effectively.

Industrial case: A chemical plant previously used cobalt-based carbide seal rings in their sulfuric acid pumps. The rings corroded and leaked after 3 months. Switching to nickel-bonded tungsten carbide extended the seal life to 18 months, with no corrosion-related failures.

Cobalt becomes brittle at extremely low temperatures (below -40°C / -40°F), which can cause tungsten carbide to crack under stress. Nickel retains its toughness even in freezing environments, making it a better choice for cold applications.

• Common applications:
  • Parts in cryogenic equipment (e.g., liquid nitrogen tanks, refrigerated transport systems).
  • Wear liners in Arctic mining operations (temperatures often drop to -50°C).
  • Valves in natural gas processing (where gas cooling can create sub-zero conditions).
• Why it works: Nickel’s crystal structure doesn’t change at low temperatures, so it maintains flexibility to absorb impact—preventing the tungsten carbide crystals from fracturing.

In niche cases, nickel is used to meet non-mechanical requirements:

• Biocompatibility: Some medical-grade tungsten carbide (used in surgical tools or implant components) uses nickel-free binders, but in rare cases, nickel alloys are used to match body tissue compatibility (though this is less common than titanium-based alternatives).
• Electrical conductivity: Nickel has better electrical conductivity than cobalt, so it’s used in tungsten carbide parts for electrical contacts or electrodes (e.g., in welding equipment or sensors).

If you’re choosing between the two, it’s important to understand how they stack up in critical areas. Here’s a straightforward comparison:

Let’s clear up common misunderstandings that can lead to wrong material choices:

1. Myth: “Nickel-based tungsten carbide is ‘better’ than cobalt-based.”
   Fact: It’s not about “better”—it’s about “fit for purpose.” Nickel-based grades excel in corrosion/low-temp scenarios, but they’re more expensive and slightly less hard. For general use (like a woodworking cutter), cobalt-based is the better choice.

2. Myth: “All corrosion-resistant tungsten carbide contains nickel.”
   Fact: Nickel is one option, but not the only one. Some grades use cobalt-chromium alloys or even ceramic binders for corrosion resistance—nickel is just the most common choice for industrial applications.

3. Myth: “Nickel in tungsten carbide is a health risk.”
   Fact: For industrial use, the risk is minimal. Nickel can cause skin irritation in sensitive individuals, but tungsten carbide parts are solid (not powdery) and rarely come into direct, prolonged contact with skin. However, if you’re working with nickel-based carbide dust (e.g., during grinding), standard PPE (masks, gloves) should be worn—just like with any industrial dust.

If you’re unsure about an existing part, here are three simple ways to check:

1. Check the product specs: The manufacturer’s datasheet will list the binder type (e.g., “10% cobalt” or “12% nickel”). This is the most reliable method.
2. Visual inspection: Nickel-based grades often have a slightly paler, more matte gray finish compared to the warmer silver-gray of cobalt-based carbide. (Note: This is a rough guide—surface finish can affect color too.)
3. Corrosion test (for new parts): Rub a small area with a cotton swab dipped in dilute hydrochloric acid. Cobalt-based carbide will leave a greenish stain (from cobalt chloride), while nickel-based will leave little to no stain. (Only do this on unused parts—acid can damage working components.)

To answer the original question: Most tungsten carbide does not contain nickel, but nickel is used in specialized grades for corrosion resistance, low temperatures, or niche needs. The key is to match the binder type to your application:

• For general wear, freshwater, or room-temperature use: Stick with cobalt-based tungsten carbide (cost-effective, high hardness).
• For chemicals, saltwater, or freezing temperatures: Choose nickel-based tungsten carbide (reliable, long-lasting).

If you’re unsure which grade fits your equipment—whether it’s a marine pump seal or an Arctic mining liner—feel free to reach out. We can help assess your工况 and recommend the right binder type, ensuring your tungsten carbide parts perform as expected.