HDA series are high-density Boron Nitride agglomerated particles. The tap density can reach 0.7g/cm³. The products contain single crystal Boron Nitride which is compacted and densified to materials with very low porosity. At present, HDA series comes in two specifications. One is a larger agglomerate with increased Boron Oxide content and D₅₀of about 210 μm. Another one is smal agglomerated product with low Boron Oxide content and  D₅₀ of about 22 μm.

HDA series high density Boron Nitride overcomes the aspect ratio of platelet like particles due to its aggregate morphology and the highly isotropic thermal conductivity in all directions.In some occasions where thermal conductivity is required and thickness is not considered, such as brake pads, the HDA specification of large particles has a large thermal conductivity cross section and can transfer heat as quickly as possible. In other occasions where both thermal conductivity and thickness are required, small agglomerated particles HDA can be used.