Generally, users pay more attention to the D50 value, D10, and D90 of white aluminum oxide powder, and pay less attention to the span of the micro-sized powder. The span of the micro-sized powder is a more strict index to show the concentration of the particle size of the micro powder. The relationship between span and D50 is:
Span = (D90-D10)/D50. The smaller the value, the more the concentration of the particle size of powder products.
Taking the white aluminum oxide powder JIS4000 as an example, the results of the random inspection of different batches by our Laboratory are as follows:
| Batch NO. | D10 | D50 | D90 | Span |
| 1 | 1.80 | 3.08 | 4.54 | 0.89 |
| 2 | 1.88 | 3.19 | 4.61 | 0.86 |
| 3 | 1.82 | 3.12 | 4.56 | 0.88 |
| 4 | 1.87 | 3.18 | 4.60 | 0.86 |
| 5 | 1.70 | 2.90 | 4.22 | 0.87 |
| 6 | 1.78 | 3.06 | 4.52 | 0.90 |
| 7 | 1.87 | 3.16 | 4.57 | 0.85 |
| 8 | 1.84 | 3.14 | 4.57 | 0.87 |
| 9 | 1.86 | 3.17 | 4.59 | 0.86 |
| 10 | 1.77 | 3.04 | 4.51 | 0.90 |
| 11 | 1.94 | 3.25 | 4.63 | 0.83 |
| 12 | 1.91 | 3.21 | 4.60 | 0.84 |
| 13 | 1.76 | 2.97 | 4.26 | 0.84 |
| 14 | 1.89 | 3.18 | 4.60 | 0.85 |
| 15 | 1.82 | 3.11 | 4.55 | 0.88 |
| 16 | 1.73 | 2.94 | 4.24 | 0.85 |
| 17 | 1.90 | 3.19 | 4.59 | 0.84 |
| 18 | 1.88 | 3.19 | 4.60 | 0.85 |
| 19 | 1.70 | 2.90 | 4.22 | 0.87 |
| 20 | 1.85 | 3.14 | 4.56 | 0.86 |
| 21 | 1.85 | 3.15 | 4.57 | 0.86 |
| 22 | 1.87 | 3.15 | 4.57 | 0.86 |
| 23 | 1.86 | 3.16 | 4.58 | 0.86 |
| 24 | 1.86 | 3.15 | 4.57 | 0.86 |
| 25 | 1.87 | 3.16 | 4.58 | 0.86 |
The span of white aluminum oxide powder JIS4000 is less than 0.9, which is suitable for applications with strict requirements on the particle size range, such as grinding and ceramic products.
