In industrial high-temperature scenarios (such as metal smelting, aero-engine components, and high-temperature molds), the core of material selection lies in "high-temperature resistance + adaptation to working condition requirements." Cemented carbide and ceramic are the two most commonly used high-temperature resistant materials, but their advantageous scenarios are distinctly different. Cemented carbide (tungsten carbide + cobalt) excels in high-temperature environments with loads and vibrations, thanks to its balanced properties of "high-temperature resistance + impact resistance." Ceramic, on the other hand, stands out for its "higher temperature resistance limit + strong oxidation resistance," making it suitable for static high-temperature scenarios without impact. There is no absolute "which is better" between the two; the key depends on factors such as the temperature range in specific working conditions, the presence of impact/load, and the type of corrosive medium. This article will analyze the applicable boundaries of the two from three dimensions—core high-temperature performance, key indicator comparison, and typical scenario recommendations—to help you accurately select the right high-temperature material.
1. First, Clarify: Core High-Temperature Properties of Cemented Carbide and Ceramic
To determine which is more suitable for high-temperature working conditions, we first need to understand their "intrinsic performance" at high temperatures. Their principles of high-temperature resistance and shortcomings differ significantly, directly determining their applicable scenarios.
1.1 High-Temperature Properties of Cemented Carbide (Tungsten Carbide + Cobalt): Balancing Temperature Resistance and Toughness
The high-temperature resistance of cemented carbide stems from the inherent stability of tungsten carbide (WC) and the bonding and buffering effect of cobalt (Co). Its core advantage at high temperatures is "non-brittle and load-bearing":
- Temperature Resistance Range: Continuous operating temperature is 600–800°C, and it can withstand 1000°C for short periods (above 800°C, cobalt will slightly soften but not completely flow away, still able to bond tungsten carbide grains).
- High-Temperature Hardness: At 800°C, the hardness retention rate is ≥90% (HRA 80–85), far higher than that of ordinary steel (hardness retention rate below 50% at 500°C), enabling it to maintain functions such as cutting and pressure bearing.
- Impact Resistance: The toughness of cobalt still works at high temperatures, capable of buffering vibrations and impacts (e.g., drill bits in high-temperature mining environments will not crack like ceramics when encountering hard rock).
- Shortcomings: When used for a long time above 800°C, the surface will slowly oxidize (forming WO₃), and the softening of cobalt will cause a slight decrease in overall strength, making it unsuitable for long-term working conditions above 1000°C.
1.2 High-Temperature Properties of Ceramic: High Temperature Resistance but High Brittleness
Common high-temperature resistant ceramics in industry are mainly alumina ceramics and silicon nitride ceramics. Their high-temperature resistance comes from "high melting point + stable crystal structure," with the core advantage of "high temperature resistance and non-oxidation," but their shortcomings are also obvious:
- Temperature Resistance Range: Continuous operating temperature is 1000–1400°C (melting point of alumina ceramic is 2054°C, and that of silicon nitride ceramic is 1900°C), much higher than that of cemented carbide.
- High-Temperature Hardness: At 1000°C, the hardness retention rate is ≥95% (HRA 85–90), and there is almost no oxidation (ceramics themselves are oxides/nitrides and do not react with air at high temperatures).
- Impact Resistance: It is brittle at room temperature, and the brittleness becomes more obvious at high temperatures (especially above 1000°C). Slight impacts (such as equipment vibration and material collision) may cause cracking or fragmentation.
- Shortcomings: It cannot withstand impact and alternating loads, and is difficult to process (unlike cemented carbide, which can be milled and drilled; ceramics can only be formed by sintering), making it difficult to control precision.
2. Key Indicator Comparison: Cemented Carbide vs. Ceramic—High-Temperature Performance at a Glance
To more intuitively see the differences, we compare the two from "6 key indicators most concerned in high-temperature working conditions" (data based on industrially commonly used YG8 cemented carbide and 95% alumina ceramic):
| Comparison Indicator | Cemented Carbide (YG8) | Ceramic (95% Alumina) | Summary of Core Differences |
|---|---|---|---|
| Continuous Operating Temperature | 600–800°C | 1000–1200°C | Ceramic’s maximum temperature resistance is 400–500°C higher than that of cemented carbide |
| Hardness Retention at 1000°C | ≤60% (HRA 55–60, unable to work normally) | ≥90% (HRA 80–85, able to work normally) | Ceramic has a significant hardness advantage above 1000°C |
| High-Temperature Impact Resistance (300°C) | Impact Toughness ≥15 J/cm² | Impact Toughness ≤3 J/cm² | The impact resistance of cemented carbide is more than 5 times that of ceramic |
| High-Temperature Corrosion Resistance (Dilute Sulfuric Acid) | Slight Surface Corrosion (cobalt is easily eroded by acid) | No Corrosion (strong chemical inertness of ceramic) | Ceramic is superior to cemented carbide in acid and alkali corrosion resistance |
| High-Temperature Machinability | Milling and Drilling Available (special tools required) | Almost Unmachinable (can only be formed by sintering) | Cemented carbide is suitable for complex parts requiring post-processing |
| Cost (Same Size) | 1x (benchmark) | 1.5–3x | Ceramic has higher cost and higher scrap rate (due to fragmentation) |
3. Scenario-Based Recommendations: Choose Correctly to Avoid Mistakes in High-Temperature Working Conditions
Understanding the performance differences, the next step is to "match scenarios to materials"—select the more suitable material based on the "temperature + impact + functional requirements" of specific working conditions:
3.1 Scenario 1: High Temperature Without Impact, Static Pressure Bearing/Insulation—Choose Ceramic
Suitable for static scenarios with "high temperature, no vibration, and no collision," such as:
- High-temperature furnace liners (1000–1200°C, only need to withstand high temperature and slight material erosion, no impact);
- High-temperature insulating parts for semiconductors (1100°C, need high-temperature resistance and insulation, no load impact);
- High-temperature thermocouple protection tubes (1200°C, inserted into molten metal, only subject to high temperature and corrosion, no vibration);
- Reason: Ceramic’s advantages of high temperature resistance limit and oxidation resistance can be fully utilized, and there is no need to worry about impact issues, enabling long-term stable operation.
3.2 Scenario 2: High Temperature With Impact and Load (Cutting/Drilling/Pressure Bearing)—Choose Cemented Carbide
Suitable for dynamic scenarios with "temperature of 600–800°C, vibration or load," such as:
- High-temperature metal cutting tools (700–800°C, need to withstand impact force and friction during cutting, ceramic tools are prone to chipping);
- Drill bits for high-temperature mining environments (600–700°C, need impact resistance when drilling into hard rock, ceramic drill bits will crack after 1–2 impacts);
- High-temperature die-casting molds for aluminum alloys (400–500°C, need to withstand die-casting pressure and metal flow impact, ceramic molds are prone to cracking);
- Reason: The balanced properties of "high-temperature hardness + impact resistance" of cemented carbide enable it to avoid failure due to impact while bearing loads, while the brittleness of ceramic is a "fatal shortcoming" in such scenarios.
3.3 Scenario 3: High Temperature + Corrosive Medium—Choose Material Based on Medium Type
- If the medium is strong acid/alkali (such as high-temperature dilute sulfuric acid, sodium hydroxide solution): Choose ceramic (ceramic has strong chemical inertness and does not react with acid/alkali, while cobalt in cemented carbide is easily eroded by acid);
- If the medium is molten metal (such as aluminum alloy, zinc alloy): Choose cemented carbide (ceramic is prone to react with molten metal, leading to surface spalling, while cemented carbide has good compatibility with most molten metals);
- If the medium is high-temperature air/flue gas: Both are acceptable (ceramic has no oxidation, and cemented carbide has slow oxidation below 800°C, whose oxidation resistance can be improved by surface coating such as TiN).
3.4 Scenario 4: High Temperature + High-Precision Processing Requirements—Choose Cemented Carbide
Suitable for high-temperature working conditions where "parts have complex structures and high-precision requirements," such as:
- High-temperature precision gears for aero-engines (600–700°C, need to mill tooth profiles, and ceramic cannot process high-precision tooth surfaces);
- High-temperature valve cores (500–600°C, need to drill holes and grind sealing surfaces, and ceramic cannot be finely processed after sintering);
- Reason: Cemented carbide can achieve high precision (tolerance ≤0.005mm) through processes such as milling and grinding, while ceramic can only be formed by mold sintering, making it difficult to control precision (tolerance is usually ≥0.05mm), which cannot meet the requirements of precision components.
4. Common Misconceptions: Don’t Be Misled by "High Temperature Resistance"—Correct Selection Is the Key
In actual material selection, many people fall into the misunderstanding that "ceramic has high temperature resistance, so ceramic should be chosen for all high-temperature working conditions," leading to equipment failures or cost waste. The following are two common misconceptions that need to be corrected:
Misconception 1: "If the temperature exceeds 800°C, ceramic must be chosen"
Fact: If there is impact or load in high-temperature working conditions, even if the temperature is 800–900°C, ceramic is not suitable. For example, a factory once used ceramic tools to cut stainless steel at 800°C, but the tools cracked immediately after the first cutting impact. After switching to cemented carbide tools (with TiN anti-oxidation coating on the surface), although the continuous operating temperature can only reach 800°C, it can still work stably by "cooling for 10 minutes every 2 hours," and its service life is more than 5 times that of ceramic tools.
Misconception 2: "Cemented carbide has low temperature resistance and is less durable than ceramic"
Fact: In impact scenarios at 600–800°C, the durability of cemented carbide is far better than that of ceramic. For example, the average service life of cemented carbide drill bits in high-temperature mining environments is 200–300 hours, while that of ceramic drill bits is less than 10 hours (mostly due to impact fragmentation). Moreover, the processing and maintenance costs of cemented carbide are lower, resulting in higher overall cost-effectiveness.
Conclusion: Choose Cemented Carbide or Ceramic—Look at the "Three Key Factors of Working Conditions"
When selecting materials for high-temperature working conditions, there is no need to worry about "which is more advanced." You only need to clarify three core factors:
- Temperature Range: Choose ceramic for temperatures above 1000°C without impact; choose cemented carbide for temperatures of 600–800°C with impact/load.
- Impact/Load: If there is vibration, collision, or cutting force, cemented carbide is a must; if it is static without impact, ceramic can be considered.
- Processing/Precision: If milling, drilling, or high precision (tolerance ≤0.01mm) is required, choose cemented carbide; if it is simple in shape and has no precision requirements, ceramic can be selected.
As a professional in the tungsten carbide industry, when recommending cemented carbide, you should focus on emphasizing its advantages of "high-temperature impact resistance + easy processing," and make accurate recommendations for high-temperature scenarios with impact (such as high-temperature cutting and high-temperature drill bits for mining). If the customer’s working conditions involve long-term use above 1000°C without impact, you can also objectively recommend ceramic to demonstrate professional neutrality.
Would you like me to compile a High-Temperature Working Condition Material Selection Comparison Table? This table includes recommended materials, models, and precautions corresponding to different temperatures, impact levels, and medium types, making it easy for you or your customers to quickly match working conditions and avoid selection mistakes.