34
S. Gupta
Fig. 8 Backscattered Electron (BSE) Field Emission Scanning Electron Microscope (FESEM)
micrographs of a HTS4-35-5, and b HTS4-35-5 (higher magnification). (Color figure online)
This study shows that we can design etched Ti 3 AlC 2 particles in dry and powder
state. It is hypothesized that these particles can be further used for enhancing the
properties of composites (Fig. 8).
Experimental Procedure
TiH 2 (Part number 209279 (−325 mesh and 98% pure) Sigma-Aldrich, St. Louis,
MO), Aluminum (Al) (Part number 11067 (7–15 micron powder and 99.5% pure)
Alfa Aesar, Haverhill, MA) and Titanium Carbide (TiC) (Part number 40178 (~2
micron powder and 99.5% pure) Alfa Aesar, Haverhill, MA) were mixed in the
molar ratio of 1:1.1:2 to fabricate Ti 3 AlC 2 by using a ball mill (8000 M mixer Mill,
SPEX SamplePrep, Metuchen, NJ). Briefly, the powers were then dry cold pressed
into compacts after mixing the powders with 10 wt% PVA. Thereafter, the pellets
were annealed at 750 °C for 2 h and then heated up to 1400 °C for 2 h at a heating rate
of 10 °C/min. For further details, please refer to Dey [104]. The sintered powders
were then milled and then sieved to −325 mesh for further analysis.
Ti 3 AlC 2 particulates were partially etched by using HCl (ACS reagent 37%, Sigma
Aldrich, St. Louis, MO) and LiF (BioUltra, ≥99.0%, Sigma Aldrich, St. Louis, MO)
as etchants in different proportions (Table 1). Initially, the required amount of LiF
was dissolved in 40 ml of 12 M HCl by stirring for ~5 min. Thereafter, ~1 g of
Ti 3 AlC 2 was added to the stirring solution. The resulting suspension was stirred for
~24 h under ambient conditions. The resulting suspension was then centrifuged at
~3000 rpm for ~5 min, and the resultant filtrate was drained. Thereafter, fresh DI
(distilled) water was added to the residue. The suspension was centrifuged again for
5 min. This cycle was continued for several cycles until the pH was ~6 by using a
pH paper. The resulting slurry was then dried at 100 °C for 24 h. The dried powder
was then sieved until −325 mesh, and then it was stored in a plastic bag.
S. Gupta
Fig. 8 Backscattered Electron (BSE) Field Emission Scanning Electron Microscope (FESEM)
micrographs of a HTS4-35-5, and b HTS4-35-5 (higher magnification). (Color figure online)
This study shows that we can design etched Ti 3 AlC 2 particles in dry and powder
state. It is hypothesized that these particles can be further used for enhancing the
properties of composites (Fig. 8).
Experimental Procedure
TiH 2 (Part number 209279 (−325 mesh and 98% pure) Sigma-Aldrich, St. Louis,
MO), Aluminum (Al) (Part number 11067 (7–15 micron powder and 99.5% pure)
Alfa Aesar, Haverhill, MA) and Titanium Carbide (TiC) (Part number 40178 (~2
micron powder and 99.5% pure) Alfa Aesar, Haverhill, MA) were mixed in the
molar ratio of 1:1.1:2 to fabricate Ti 3 AlC 2 by using a ball mill (8000 M mixer Mill,
SPEX SamplePrep, Metuchen, NJ). Briefly, the powers were then dry cold pressed
into compacts after mixing the powders with 10 wt% PVA. Thereafter, the pellets
were annealed at 750 °C for 2 h and then heated up to 1400 °C for 2 h at a heating rate
of 10 °C/min. For further details, please refer to Dey [104]. The sintered powders
were then milled and then sieved to −325 mesh for further analysis.
Ti 3 AlC 2 particulates were partially etched by using HCl (ACS reagent 37%, Sigma
Aldrich, St. Louis, MO) and LiF (BioUltra, ≥99.0%, Sigma Aldrich, St. Louis, MO)
as etchants in different proportions (Table 1). Initially, the required amount of LiF
was dissolved in 40 ml of 12 M HCl by stirring for ~5 min. Thereafter, ~1 g of
Ti 3 AlC 2 was added to the stirring solution. The resulting suspension was stirred for
~24 h under ambient conditions. The resulting suspension was then centrifuged at
~3000 rpm for ~5 min, and the resultant filtrate was drained. Thereafter, fresh DI
(distilled) water was added to the residue. The suspension was centrifuged again for
5 min. This cycle was continued for several cycles until the pH was ~6 by using a
pH paper. The resulting slurry was then dried at 100 °C for 24 h. The dried powder
was then sieved until −325 mesh, and then it was stored in a plastic bag.